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]: Collars come in ____ shapes.\Question: Choose the right answer from options given a) six b) two c) four d) zero
[EX A]: b

[EX Q]: Vaporization can occur in temperatures as low as ____ degrees.\Question: Choose the right answer from options given a) one b) zero c) eight d) two
[EX A]: b

[EX Q]: Birds have ____ beak, two wings, and two feet.\Question: Choose the right answer from options given a) zero b) ten c) five d) one
[EX A]:
d