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: Some taxonomists classify only ____ species though.\Question: Choose the right answer from options given a) one b) six c) two d) three
Example Output: c

Example Input: Butterflies have ____ stages in their life cycle.\Question: Choose the right answer from options given a) two b) four c) no d) eight
Example Output: b

Example Input: Cats have ____ sets of vocal cords.\Question: Choose the right answer from options given a) zero b) nine c) two d) three
Example Output:
c