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: Fever usually lasts for an average of ____ days in adults.\Question: Choose the right answer from options given a) zero b) three c) nine d) two

Output: b


Input: Consider Input: Food chains consist of ____ trophic levels.\Question: Choose the right answer from options given a) ten b) three c) one d) four

Output: d


Input: Consider Input: Rats only live about ____ years.\Question: Choose the right answer from options given a) four b) three c) ten d) two


Output: d