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:
Astronauts sleep only ____ hours each night, on average.\Question: Choose the right answer from options given a) six b) one c) four d) seven

Ex Output:
a


Ex Input:
Mosquitoes have ____ distinctive life stages, with the first three stages being spent in the water.\Question: Choose the right answer from options given a) four b) zero c) nine d) five

Ex Output:
a


Ex Input:
Most sailing ships have between one and ____ mast but some have four.\Question: Choose the right answer from options given a) zero b) three c) eight d) two

Ex Output:

b