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]: Astronomers fall in ____ classes - professionals and amateurs.\Question: Choose the right answer from options given a) two b) four c) six d) zero
[EX A]: a

[EX Q]: Some taxonomists classify only ____ species though.\Question: Choose the right answer from options given a) one b) six c) two d) three
[EX A]: c

[EX Q]: Some adjectives have ____ forms, others have four.\Question: Choose the right answer from options given a) no b) five c) two d) eight
[EX A]:
c