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]: Mechanical stability comes from having fused quartz, in ____ gravity, cold.\Question: Choose the right answer from options given a) five b) zero c) six d) two
[A]: b


[Q]: Some skulls show the marks of up to ____ bullets.\Question: Choose the right answer from options given a) five b) three c) eight d) six
[A]: d


[Q]: Couples often date from ____ to three years before getting engaged.\Question: Choose the right answer from options given a) one b) seven c) ten d) two
[A]:
a