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: Calves remain hidden for much of the time, and are weaned by ____ months of age.\Question: Choose the right answer from options given a) six b) three c) eight d) one
Example Output: b

Example Input: Most females are sexually mature at about ____ to six years.\Question: Choose the right answer from options given a) eight b) nine c) five d) two
Example Output: c

Example Input: Pigs grow very quickly and are normally ready for sale at ____ to six months of age.\Question: Choose the right answer from options given a) no b) four c) five d) two
Example Output:
b