You will be given a definition of a task first, then some input of the task.
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').

Most dogs start to mature at two to ____ years.\Question: Choose the right answer from options given a) ten b) four c) three d) seven
Output:
c