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]: Uncontrolled diabetes can increase risk by up to ____ times.\Question: Choose the right answer from options given a) five b) four c) seven d) eight
[EX A]: b

[EX Q]: Some European countries require ____ years of education.\Question: Choose the right answer from options given a) no b) nine c) six d) three
[EX A]: d

[EX Q]: Most species go through ____ larval instars .\Question: Choose the right answer from options given a) two b) seven c) four d) zero
[EX A]:
c