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: All cattle have a ____ chambered stomach, consisting of a rumen, reticulum, omasum and abomasum.\Question: Choose the right answer from options given a) ten b) four c) six d) two
Example Output: b

Example Input: Longitude is relative to ____ degrees, along which Greenwich, England is located.\Question: Choose the right answer from options given a) six b) seven c) zero d) two
Example Output:
c