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').

Input: Consider 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

Output: c


Input: Consider Input: Pneumatic motor is a six-point unit with ____ pneumatics facing up and three facing down.\Question: Choose the right answer from options given a) five b) no c) three d) nine

Output: c


Input: Consider Input: Fish are sexually mature at age three and ____ year old fish are common.\Question: Choose the right answer from options given a) four b) three c) six d) seven


Output: c