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: Bucks grow antlers each year that reach ____ to six feet in spread.\Question: Choose the right answer from options given a) seven b) one c) three d) five
Example Output: d

Example Input: Metabolism have ____ stages-catabolism and anabolism.\Question: Choose the right answer from options given a) nine b) two c) five d) three
Example Output: b

Example Input: Most nematodes molt ____ times.\Question: Choose the right answer from options given a) two b) four c) one d) ten
Example Output:
b