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: Eastern cottontails have ____ different fur coats each year.\Question: Choose the right answer from options given a) five b) two c) eight d) six
Example Output: b

Example Input: Marriage is the legal union of ____ people.\Question: Choose the right answer from options given a) one b) no c) five d) two
Example Output: d

Example Input: Wetlands perform ____ important functions in relation to climate change.\Question: Choose the right answer from options given a) seven b) ten c) two d) zero
Example Output:
c