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').

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

A: a
****
Q: All cattle have a ____ chambered stomach, consisting of a rumen, reticulum, omasum and abomasum.\Question: Choose the right answer from options given a) ten b) four c) six d) two

A: b
****
Q: Unmarried women are ____ to five times more likely to abort than married.\Question: Choose the right answer from options given a) eight b) ten c) zero d) four

A:
d
****