Antonyms

Sallow refers to a sickly, yellowish color. Ruddy refers to red or reddish in colour.

Halcyon means calm; peaceful; tranquil. Rough means 'characterized by unnecessary violence'.

Urbane is used for something reflecting elegance, sophistication, etc., especially in expression. Naive means having or showing unaffected simplicity of nature or absence of artificiality; unsophisticated. 

Irascible means having or showing a tendency to be easily angered. Calm is opposite in meaning to it.

Spurious means not genuine, authentic, or true.

Provident means economical; frugal or thrifty. Prodigal is opposite to it in meaning.

Irreverent means showing a lack of respect or disrespect. Pious means showing reverence, especially toward God, and is the strongest antonym among the options. While 'respecting' appears related, it's a participle form rather than an adjective. Pious directly captures the quality of being reverent and dutiful in a way that opposes irreverence.

Haggard describes someone looking exhausted, worn, and weary. Plump (full and rounded) is the opposite physical state - suggesting health and nourishment rather than exhaustion. Inspired (mentally stimulated) is a mental state, not physical appearance. Shrewish means bad-tempered, which is unrelated.

Laconic means using very few words or concise in speech. Verbose means using more words than needed - the direct opposite. The other options are unrelated: milky (containing milk), wicked (evil), flagrant (openly shameful), and derelict (negligent) have no semantic relationship to conciseness.

Latent means existing but not yet developed or manifest (hidden, concealed). Obvious means easily seen or understood - the direct opposite. Early is incorrect because latent doesn't mean 'late' - it means 'not visible'. Hidden is actually a synonym, not an antonym.

Hilarity means extreme amusement or boisterous laughter. Gloom means sadness, darkness, or lack of cheer - the direct emotional opposite. Heartiness actually relates to robustness and could be associated with laughter. Casualty means someone killed or injured, unrelated. Paucity means scarcity.

'Heretic', like an iconoclast, is opposed to and questions dogmatic beliefs. So, heretic is a person who does not go by faith alone and might be considered a non-believer.

Granulate means to form into grains or small particles. Crystallize means to form definite crystals - the opposite process. Crush (option C) is similar to granulation, not opposite. Store, magnify, and sweeten are unrelated processes.

Gratuitous means lacking good reason, unwarranted, or uncalled for. Its direct opposite is warranted, which implies being justified or backed by good reasons.

Heterogeneous means diverse or composed of different kinds. Similar means alike in nature or characteristics - the direct opposite. Unlike is actually a synonym of heterogeneous. Orthodox means conventional, pagan relates to religion, and banished means expelled.