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').
--------
Question: Most children have a vocabulary of eight to ____ words, including names, by eighteen months of age.\Question: Choose the right answer from options given a) ten b) one c) seven d) eight

Answer: a


Question: 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

Answer: a


Question: Masturbation can get really old after ____ or seven years.\Question: Choose the right answer from options given a) zero b) nine c) two d) six

Answer:
d