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:
Ostriches have ____ stomachs.\Question: Choose the right answer from options given a) four b) nine c) eight d) three

Ex Output:
d

Ex Input:
Genetic mapping divides the chromosomes in ____ bands.\Question: Choose the right answer from options given a) ten b) two c) four d) nine

Ex Output:
b

Ex Input:
Many children remain, on average, ____ to six years without permanent homes.\Question: Choose the right answer from options given a) zero b) ten c) four d) eight

Ex Output:
c