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: Human feet bear average five to ____ hundreds tons of weight everyday.\Question: Choose the right answer from options given a) six b) eight c) five d) nine
Example Output: a

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: Female hummingbirds are born with ____ ovaries.\Question: Choose the right answer from options given a) five b) two c) four d) ten
Example Output:
b