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]: Whales are divided into ____ categories, based on their teeth.\Question: Choose the right answer from options given a) two b) four c) nine d) ten
[EX A]: a

[EX Q]: All baleen whales have ____ blow holes.\Question: Choose the right answer from options given a) zero b) four c) seven d) two
[EX A]: d

[EX Q]: Communists believe in things which have ____ basis in reality.\Question: Choose the right answer from options given a) five b) eight c) no d) seven
[EX A]:
c