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]: Matter exists in ____ forms, solid, fluid and plasma.\Question: Choose the right answer from options given a) ten b) nine c) three d) five
[EX A]: c

[EX Q]: Background radiation comes from ____ sources.\Question: Choose the right answer from options given a) zero b) three c) four d) no
[EX A]: b

[EX Q]: Substance abusers have ____ times the absentee rate of non-abusers.\Question: Choose the right answer from options given a) one b) nine c) four d) three
[EX A]:
c