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: Cats can harbor a heartworm infection at any age from ____ months to seventeen years.\Question: Choose the right answer from options given a) one b) six c) nine d) three

Output: c

Input: Consider Input: All spider mites have ____ legs and a lack of a separate head.\Question: Choose the right answer from options given a) eight b) four c) ten d) one

Output: a

Input: Consider Input: Parvo can survive in the environment for as long as ____ months.\Question: Choose the right answer from options given a) ten b) six c) no d) nine
Output: b