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').

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

Human rabies is extremely rare, and there have been no cases in Oregon in the last ____ years.\Question: Choose the right answer from options given a) nine b) five c) ten d) eight
d

Heart disease is ____ times more common amongst smokers.\Question: Choose the right answer from options given a) three b) five c) two d) nine

a