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]: National forests have regulations that restrict ____ wheeler use to established roads.\Question: Choose the right answer from options given a) no b) four c) six d) nine
[A]: b


[Q]: Widowed men are ____ times as likely to be murdered.\Question: Choose the right answer from options given a) two b) four c) three d) no
[A]: b


[Q]: Neutrons consist of ____ up quark and two down quarks.\Question: Choose the right answer from options given a) one b) five c) seven d) ten
[A]:
a