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').

Ex Input:
Circles mark the approximate locations of ____ recently discovered solar systems.\Question: Choose the right answer from options given a) four b) no c) zero d) nine

Ex Output:
a


Ex 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

Ex Output:
c


Ex Input:
Blankets can take up to ____ days to dry in the colder months.\Question: Choose the right answer from options given a) eight b) three c) two d) nine

Ex Output:

b