See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

**Optical Activity Analysis** Optical activity requires the presence of at least one **chiral center** (stereocenter) — a carbon atom bonded to four different groups. **Option (A):** Tetrahydroquinoline derivative - Contains a fused ring system with a secondary amine - The saturated ring junction carbon is bonded to: H, N, two different ring carbons - **Has 1 chiral center** → Optically active ✓ **Option (B):** Naphthalene derivative with carboxylic acids - Both carboxylic acid groups are attached to the aromatic ring - No saturated chiral center exists (aromatic carbons cannot be chiral) - **No chiral center** → Optically inactive ✗ **Option (C):** Tetrahydronaphthalene with methyl and carboxylic acid groups - Symmetric structure: methyl groups on one ring, carboxylic acids on the other - **No chiral center** (all stereocenters have plane of symmetry or are achiral) → Optically inactive ✗ **Option (D):** Indole derivative with lactam - Aromatic heterocycle without saturated chiral centers - **No chiral center** → Optically inactive ✗ **Answer: (A)** is the only compound with an asymmetric carbon atom in a saturated environment, making it optically active.