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]: Heat pumps give off ____ fumes or harmful products of combustion.\Question: Choose the right answer from options given a) four b) zero c) six d) no
[EX A]: d

[EX Q]: Vampires generally are male, and rabies is ____ times more frequent in men than in women.\Question: Choose the right answer from options given a) no b) two c) zero d) seven
[EX A]: d

[EX Q]: Surface area is the sum of the faces, or surfaces, of a ____ dimensional shape.\Question: Choose the right answer from options given a) no b) eight c) three d) six
[EX A]:
c