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: Sexual maturity occurs at three to four years for females and ____ to five years for males.\Question: Choose the right answer from options given a) nine b) seven c) five d) four
Example Output: d

Example Input: Harbor porpoises live in groups averaging one to ____ individuals and are very skittish.\Question: Choose the right answer from options given a) seven b) five c) two d) three
Example Output: d

Example Input: Some signs have as many as ____ different coats of color.\Question: Choose the right answer from options given a) five b) no c) nine d) six
Example Output:
c