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: National forests have regulations that restrict ____ wheeler use to established roads.\Question: Choose the right answer from options given a) no b) four c) six d) nine
Example Output: b

Example Input: Trappers have ____ genders and reproduce sexually.\Question: Choose the right answer from options given a) zero b) two c) five d) one
Example Output: b

Example Input: Newborn kittens develop sight during the first three or ____ weeks of life.\Question: Choose the right answer from options given a) four b) nine c) zero d) six
Example Output:
a