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: ATMs are expensive machines with an average useful life of ____ to fifteen years.\Question: Choose the right answer from options given a) nine b) eight c) ten d) two

Output: c


Input: Consider Input: Chipmunks produce one or ____ litters a year.\Question: Choose the right answer from options given a) three b) one c) ten d) two

Output: d


Input: Consider Input: Ammonia is found in ____ forms in the pond.\Question: Choose the right answer from options given a) two b) three c) seven d) four


Output: a