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]: Springtails reproduce quickly usually within three to ____ weeks.\Question: Choose the right answer from options given a) five b) six c) nine d) three
[EX A]: a

[EX Q]: Rheumatic fever begins one to ____ weeks after an untreated streptococcal infection.\Question: Choose the right answer from options given a) six b) ten c) two d) zero
[EX A]: a

[EX Q]: Cattle are ruminants and have ____ stomachs.\Question: Choose the right answer from options given a) six b) five c) nine d) four
[EX A]:
d