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 have ____ sets of vocal cords.\Question: Choose the right answer from options given a) zero b) nine c) two d) three

Output: c


Input: Consider Input: Most people require roughly seven to ____ hours of sleep a night to stay alert through the day.\Question: Choose the right answer from options given a) eight b) ten c) one d) five

Output: a


Input: Consider Input: Numbers multiplied by ____ are always even.\Question: Choose the right answer from options given a) two b) six c) four d) zero


Output: c