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: 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
Example Output: c

Example Input: Plants can uptake ____ times more nutrients, and improve soil texture at the same time.\Question: Choose the right answer from options given a) no b) two c) three d) ten
Example Output: d

Example Input: Breast feeding for ____ months reduces a woman's risk for breast cancer.\Question: Choose the right answer from options given a) two b) zero c) five d) six
Example Output:
d