Why: Cup is used to drink something with the help of lips. Similarly, birds collect grass with the help of beak to make her nest. The relationship is part-to-function: lip is the part of the body used with cup for drinking, beak is the part used by bird for collecting nest material. Thus, option D completes the analogy correctly.

Why: As water of a river flows, similarly water of a pool is stagnant. The relationship is characteristic-to-object: flow describes the movement of water in a river, stagnant describes the lack of movement in a pool. Option C matches this relationship.

Why: As cat has paw, similarly horse has hoof. The relationship is body part-to-animal: paw is the specific foot structure of a cat, hoof is the specific foot structure of a horse. Option B correctly completes the analogy.

Why: Ornithologist is a specialist of birds, similarly archaeologist is a specialist of archaeology. The relationship is expert-to-field-of-study: ornithologist studies birds, archaeologist studies archaeology. Option B matches precisely.

Why: Peacock is the national bird of India, similarly bear is the national animal of Russia. The relationship is national symbol-to-country: peacock represents India, bear represents Russia. Option A completes the analogy.