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:
People can go without food for up to about ____ weeks.\Question: Choose the right answer from options given a) three b) one c) nine d) four

Ex Output:
a


Ex Input:
Brachiopods are superficially similar to bivalves, both having ____ shells.\Question: Choose the right answer from options given a) two b) eight c) seven d) one

Ex Output:
a


Ex Input:
Caterpillars are grayish with ____ pairs of blue spots and six pairs of red spots along their back.\Question: Choose the right answer from options given a) one b) five c) no d) four

Ex Output:

b