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 Q]: Metals often crystallize in a ____ dimensional version of the hexagonal closest packed structure.\Question: Choose the right answer from options given a) one b) seven c) three d) eight
[EX A]: c

[EX Q]: Most gerbils live three to ____ years and have few health problems.\Question: Choose the right answer from options given a) three b) four c) seven d) zero
[EX A]: b

[EX Q]: Some people have ____ symptoms until the liver has been quite severely damaged.\Question: Choose the right answer from options given a) eight b) no c) nine d) ten
[EX A]:
b