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: Pandas reach adulthood at about ____ years of age.\Question: Choose the right answer from options given a) eight b) seven c) five d) six
Example Output: c

Example Input: Young emus are very vulnerable to disease until they are about ____ months old.\Question: Choose the right answer from options given a) no b) ten c) six d) three
Example Output: d

Example Input: Sod webworms produce ____ to three generations each year.\Question: Choose the right answer from options given a) two b) zero c) one d) six
Example Output:
a