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:
Mosquitoes spend one to ____ days in the pupae stage.\Question: Choose the right answer from options given a) zero b) two c) five d) three

Ex Output:
b


Ex Input:
Today there are ____ federal states, each based on cultural affiliations.\Question: Choose the right answer from options given a) one b) nine c) seven d) zero

Ex Output:
b


Ex Input:
Conserved residues make similar contacts in ____ repressor-operator complexes.\Question: Choose the right answer from options given a) zero b) five c) two d) ten

Ex Output:

c