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:
Infants usually die of pneumonia or other infections before reaching ____ years of age.\Question: Choose the right answer from options given a) nine b) four c) zero d) eight

Ex Output:
b


Ex Input:
Paleontologists specialize in ____ main areas.\Question: Choose the right answer from options given a) eight b) five c) no d) six

Ex Output:
b


Ex Input:
Most camera lenses are like a ____ by six picture frame.\Question: Choose the right answer from options given a) seven b) five c) four d) three

Ex Output:

c