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: Mosquitoes have ____ distinctive life stages, with the first three stages being spent in the water.\Question: Choose the right answer from options given a) four b) zero c) nine d) five
Example Output: a

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: Wolverines reproduce every ____ or three years .\Question: Choose the right answer from options given a) eight b) ten c) two d) one
Example Output:
c