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:
Many soils have ____ major layers or horizons, top soil, subsoil and parent material.\Question: Choose the right answer from options given a) one b) two c) seven d) three

Ex Output:
d


Ex Input:
Mothers usually give birth to one, two, or ____ babies at a time.\Question: Choose the right answer from options given a) three b) zero c) five d) ten

Ex Output:
a


Ex Input:
Trees begin to form fruiting buds at around ____ years of age.\Question: Choose the right answer from options given a) zero b) one c) no d) three

Ex Output:

d