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: Bees possess ____ eyes.\Question: Choose the right answer from options given a) three b) five c) one d) ten
Example Output: b

Example Input: Elephants rise ____ inches when they inhale.\Question: Choose the right answer from options given a) two b) five c) one d) eight
Example Output: a

Example Input: Voles are prolific breeders and can produce four to ____ litters a year.\Question: Choose the right answer from options given a) four b) two c) six d) three
Example Output:
c