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]: ATMs are expensive machines with an average useful life of ____ to fifteen years.\Question: Choose the right answer from options given a) nine b) eight c) ten d) two
[EX A]: c

[EX Q]: Cleavage is good in ____ directions forming cubes.\Question: Choose the right answer from options given a) two b) three c) six d) zero
[EX A]: b

[EX Q]: Energy comes in ____ forms, which are kinetic and potential.\Question: Choose the right answer from options given a) seven b) two c) five d) no
[EX A]:
b