Step 1: Understanding the Concept:
Citrus fruits (lemon, orange, amla-like fruits) are a major natural source of vitamin C, also called ascorbic acid. It is used to prevent and treat scurvy.
Step 2: Options:
Antimicrobials, analgesics and antiseptics are classes of drugs, not substances taken from citrus fruits. Vitamin C is a specific compound obtained from them.
Final Answer:
The compound is vitamin C, option (B).
\[ \boxed{\text{Vitamin C}} \]