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:
Trinity comes from tri-unity which means ____ in one.\Question: Choose the right answer from options given a) four b) three c) eight d) zero

Ex Output:
b


Ex Input:
Embryos develop and hatch in about four weeks, then spend four to ____ months in the tadpole stage.\Question: Choose the right answer from options given a) five b) nine c) eight d) two

Ex Output:
a


Ex Input:
Poplars usually are ready for use as biomass energy at ____ years.\Question: Choose the right answer from options given a) five b) zero c) two d) four

Ex Output:

a