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').

Input: Consider Input: Sound waves travel through the air in a similar manner, but in all ____ dimensions.\Question: Choose the right answer from options given a) three b) five c) nine d) one

Output: a


Input: Consider Input: Sexual maturity is reached at about ____ years of age.\Question: Choose the right answer from options given a) five b) ten c) no d) two

Output: d


Input: Consider Input: Stoneflies are the largest of the ____ main types of trout stream insects.\Question: Choose the right answer from options given a) two b) ten c) four d) three


Output: d