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:
Ammonia is among the ____ most abundantly produced chemicals in the world.\Question: Choose the right answer from options given a) five b) zero c) no d) eight

Ex Output:
a


Ex Input:
Humans normally produce only ____ sets of teeth.\Question: Choose the right answer from options given a) nine b) eight c) two d) three

Ex Output:
c


Ex Input:
Urban families have one or ____ children.\Question: Choose the right answer from options given a) four b) two c) seven d) zero

Ex Output:

b