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

Answer: d


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

Answer: a


Question: Cartesian Coordinates can define a point in space, that is, in ____ dimensions.\Question: Choose the right answer from options given a) seven b) eight c) nine d) three

Answer:
d