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]: Electrolytic capacitors have a useful life of about ____ years.\Question: Choose the right answer from options given a) ten b) eight c) zero d) seven
[A]: a


[Q]: Spores have ____ combinations of sexes.\Question: Choose the right answer from options given a) four b) five c) seven d) three
[A]: a


[Q]: Final nymphs molt into adult males or females, also with ____ legs.\Question: Choose the right answer from options given a) eight b) three c) six d) zero
[A]:
a