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: Cats have ____ lives.\Question: Choose the right answer from options given a) five b) one c) two d) nine
Example Output: d

Example Input: Heat pumps give off ____ fumes or harmful products of combustion.\Question: Choose the right answer from options given a) four b) zero c) six d) no
Example Output: d

Example Input: Cardinals have ____ main functions in the church.\Question: Choose the right answer from options given a) five b) three c) two d) nine
Example Output:
b