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]: Summer is the hottest of the ____ temperate seasons , falling between spring and autumn .\Question: Choose the right answer from options given a) six b) four c) no d) nine
[EX A]: b

[EX Q]: Young children suffer from an average of six to ____ colds a year.\Question: Choose the right answer from options given a) ten b) eight c) two d) one
[EX A]: b

[EX Q]: Astronomical observations suggest ____ or close to zero space-time curvature.\Question: Choose the right answer from options given a) six b) zero c) ten d) seven
[EX A]:
b