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: Astronomers fall in ____ classes - professionals and amateurs.\Question: Choose the right answer from options given a) two b) four c) six d) zero

Output: a


Input: Consider Input: Statistics show that within ____ years of divorce, many people marry a second time.\Question: Choose the right answer from options given a) four b) nine c) six d) three

Output: d


Input: Consider Input: Ocelots are the most aquatic of the ____ animals.\Question: Choose the right answer from options given a) nine b) ten c) four d) eight


Output: c