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]: Carbon forms ____ bonds.\Question: Choose the right answer from options given a) five b) four c) two d) three
[EX A]: b

[EX Q]: Water is the only natural substance which exists in all ____ states of matter in nature.\Question: Choose the right answer from options given a) no b) eight c) six d) three
[EX A]: d

[EX Q]: Bowheads also boast ____ blowholes, as do all baleen whales.\Question: Choose the right answer from options given a) five b) seven c) two d) three
[EX A]:
c