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]: Evolution is dependent on ____ forces.\Question: Choose the right answer from options given a) no b) five c) two d) seven
[EX A]: c

[EX Q]: Respiratory therapists complete ____ to four years of education.\Question: Choose the right answer from options given a) one b) nine c) zero d) two
[EX A]: d

[EX Q]: Quartile values divide a sample of hospitals into ____ groups equal in number.\Question: Choose the right answer from options given a) two b) four c) three d) five
[EX A]:
b