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:
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:
Real airplanes have round engines and ____ wings.\Question: Choose the right answer from options given a) four b) six c) three d) two

Ex Output:
d


Ex Input:
Underground mining is by open stoping with ____ levels for extraction, drilling and ventilation.\Question: Choose the right answer from options given a) seven b) three c) four d) ten

Ex Output:

b