Step 1: Understanding the Concept:
Pairing each vocabulary word in List I with its direct opposite (antonym) in List II.
Step 2: Detailed Explanation:
Matching opposites:
1. Withdraw (A): To pull back or retreat $\to$ Antonym is Advance (II).
2. Heartfelt (B): Deeply felt and genuine $\to$ Sincere/Insincere match (I).
3. Pit (C): A deep hollow or depression $\to$ Antonym is Peak (summit) (III).
4. Rotund (D): Plump, round, or chubby $\to$ Antonym is Thin (IV).
Step 3: Final Answer:
Matching summary: A $\to$ II, B $\to$ I, C $\to$ III, D $\to$ IV.