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:
All mass spectrometers consist of ____ distinct regions.\Question: Choose the right answer from options given a) three b) one c) two d) zero

Ex Output:
a


Ex Input:
Amelia Island is the only territory in American history to serve under ____ flags.\Question: Choose the right answer from options given a) eight b) no c) six d) five

Ex Output:
a


Ex Input:
Efts leave the water and live on land for ____ to three years.\Question: Choose the right answer from options given a) four b) no c) six d) one

Ex Output:

d