Dicotyledons - Structure and Classification

Monochlamydeous flower has only one accessory whorl present (perianth). For example, Polygonaceae and Liliaceae.

The only dicot family bearing six cotyledons is Loranthaceae. The Loranthaceae are a family of flowering plants, which has been universally recognized by taxonomists. It consists of about 75 genera and 1,000 species of woody plants, many of them hemiparasites, all of them except three having the mistletoe habit.

Pea is a dicot exalbuminous seed. In the non-endospermic dicotyledons the endosperm is absorbed by the embryo as the latter grows within the developing seed and the cotyledons of the embryo become filled with stored food. At maturity, seeds of these species have no endosperm and are also referred to as exalbuminous seeds. The exalbuminous seeds include the legumes such as beans and peas.
Therefore, the correct answer is option A.

The fruit of a groundnut is a lomentum. In botanical terms, nut specifically refers to indehiscent fruit, the peanut is not technically a nut, but rather a legume and its fruit is a lomentum. Lomentum is a dry fruit of certain leguminous plants, having constrictions between the seeds and separating at maturity into one-seeded segments. A loment (or lomentum) is a type of indehiscent legume fruit that breaks apart at constrictions occurring between segments, so that each segment contains one seed. It is a type of schizocarp.
Thus, the correct answer is option A.

Dicots have floral parts in multiples of four or five, and their seeds contain two cotyledons. The cotyledons usually absorb the food from the endosperm first, and then provide the food for the embryo. 

The active growing region in a dicot embryo which forms shoot is the plumule. The plumule is the young shoot of a plant embryo above the cotyledons, consisting of the epicotyl and often of immature leaves. The young shoot or plumule, is said to be negatively geotropic, because it moves away from the soil it rises by the extension of either the hypocotyl.
Thus, the correct answer is option D.

The peanut or groundnut (Arachis hypogaea) is a species in the family Fabaceae. The peanut was probably first domesticated and cultivated in the valleys of Paraguay. It is an annual herbaceous plant growing 30 to 50 cm tall. Because, in botanical terms, nut specifically refers to indehiscent fruit, the peanut is not technically a nut, but rather a legume. Peanuts are often served in a similar manner to true nuts in many Western cuisines, and are often referred to as a nut in common English.
Thus, the correct answer is option C.

A. Embryo lies in the centre of endosperm. It consists of a
radicle, a plumule and two lateral cotyledons, all of which are present on a
short embryo axis. The cotyledons are thin, semi-transparent and oval in
outline. They have palmate venation. The middle costa or rib is more prominent
and bears a few lateral veins.

B. Maize- Cotyledons store food material for the embryo.

C. Pea- Cotyledons store food material for the embryo.

The production of vast amount of grain is one of the most outstanding outcome of modern agriculture. Poaceae (monocot) and fabaceae (dicot) contribute to the species, that are responsible for the vast majority of grain production worldwide.

The earliest known flowering plants date back to about 130 million years ago. According to Cronquist (evolution and classification of flowering plants, 1988), the most primitive of all living angiosperms belong to the subclass Magnoliidae. This subclass contains several primitive plant families, including the water-lily family (Nymphaeaceae), buttercup family (Ranunculaceae) and magnolia family (Magnoliaceae). 

Arachis hypogaea is the botanical name of peanut or groundnut. It is an annual herbaceous plant in the Fabaceae (legume or bean family). Although appearing as and referred to as a nut, it is actually the underground pod of a legume, rather than a true nut.

The peanut or groundnut (Arachis hypogaea) is a species in the family Fabaceae. The peanut was probably first domesticated and cultivated in the valleys of Paraguay. It is an annual herbaceous plant growing 30 to 50 cm tall. Peanut oil is often used in cooking, because it has a mild flavor and a relatively high smoke point. Due to its high monounsaturated content, it is considered healthier than saturated oils and is resistant to rancidity. There are several types of peanut oil including aromatic roasted peanut oil, refined peanut oil, extra virgin or cold pressed peanut oil and peanut extract. In the United States, refined peanut oil is exempt from allergen labeling laws.
Peanut oil is not obtained from Lathyrus odoratus (sweet pea), Pisum sativum (garden pea), Glycine max (soya) or Brassica juncea (mustard). 
Therefore, the correct answer is option C.

Dicots showing parallel venation are Calophyllum and Corymbium. 

Peanut (Arachis hypogaea) oil is the refined fixed oil obtained from the seed kernels of Arachis hypogaea. Hydrogenated peanut oil, peanut acid, and peanut glycerides are all derived from peanut oil. It is light yellow-colored oil and extremely stable, with nourishing and protective properties.

X - Hilum - it is the point of attachmnet of the ovule to its stalk or the funicle

In dicotyledonous plants, the microspore tetrads are typically arranged in a tetrahedral configuration.

Cuscuta is a plant whose embryos lack cotyledons. It is called dicot plant because the stem of cuscuta has as dicot structure. 

In groundnut, oil is stored in the seeds cotyledons.  It is a legume plant.  Each seed of groundnut has 2 cotyledons.