Given a sentence with a missing word, pick the answer option that best fills out the missing word in the sentence. Indicate each answer with its index ('a', 'b', 'c', 'd').

Example Input: Most endocrinologists see patients every ____ months throughout the pregnancy.\Question: Choose the right answer from options given a) six b) two c) zero d) three
Example Output: b

Example Input: Cats have ____ toes on their front paws, but only four touch the ground when walking.\Question: Choose the right answer from options given a) six b) nine c) five d) zero
Example Output: c

Example Input: Chicks stand on their mothers feet until they are ____ weeks old.\Question: Choose the right answer from options given a) six b) five c) ten d) eight
Example Output:
d