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]: 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
[EX A]: a

[EX Q]: Humans normally produce only ____ sets of teeth.\Question: Choose the right answer from options given a) nine b) eight c) two d) three
[EX A]: c

[EX Q]: Squirrels otherwise appear to be safe and pose almost ____ risk of transmitting rabies .\Question: Choose the right answer from options given a) seven b) one c) zero d) no
[EX A]:
c