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').

Q: Gases are perhaps the best understood of the ____ states of matter.\Question: Choose the right answer from options given a) three b) five c) nine d) zero

A: a
****
Q: Many aneurysms have ____ symptoms until they burst.\Question: Choose the right answer from options given a) no b) five c) six d) seven

A: a
****
Q: Hoof balance is ____ dimensional geometry.\Question: Choose the right answer from options given a) four b) six c) eight d) ten

A:
a
****