To answer this question, you need to understand the symbols used in deployment diagrams. Let's go through each option to understand why it is correct or incorrect:
Option A) There is no symbol because components are not allowed in deployment diagrams. - This option is incorrect. Components are indeed represented in deployment diagrams, so there is a symbol for them.
Option B) Rounded rectangle, just like a state in a state diagram - This option is incorrect. While a rounded rectangle is used to represent states in a state diagram, it is not the symbol used for components in a deployment diagram.
Option C) 3-dimensional rectangular solid (like a box) - This option is incorrect. While a 3-dimensional rectangular solid is used to represent nodes in a deployment diagram, it is not the symbol used for components.
Option D) Rectangle with tabs on its left side - This option is correct. In a deployment diagram, components are represented by rectangles with tabs on their left side. This symbol helps to differentiate components from nodes.
The correct answer is Option D. This option is correct because a rectangle with tabs on its left side is the symbol used to represent a component in a deployment diagram.