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: Most viruses have only ____ organelles.\Question: Choose the right answer from options given a) ten b) two c) four d) eight
Example Output: b

Example Input: Cats can harbor a heartworm infection at any age from ____ months to seventeen years.\Question: Choose the right answer from options given a) one b) six c) nine d) three
Example Output: c

Example Input: Medallions are ____ domes or other shapes placed around an open central space.\Question: Choose the right answer from options given a) seven b) zero c) four d) three
Example Output:
c