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: Roundworms are fairly large worms that can grow to be ____ or five inches long.\Question: Choose the right answer from options given a) no b) nine c) four d) zero
Example Output: c

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: Most indoor gyms space their protection bolts often less than ____ feet apart.\Question: Choose the right answer from options given a) four b) nine c) no d) five
Example Output:
d