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: Natural indium contains ____ isotopes.\Question: Choose the right answer from options given a) one b) eight c) two d) seven

Output: c


Input: Consider Input: Astronauts sleep only ____ hours each night, on average.\Question: Choose the right answer from options given a) six b) one c) four d) seven

Output: a


Input: Consider Input: Respect is the essential concept between any ____ life-forms.\Question: Choose the right answer from options given a) three b) ten c) two d) eight


Output: c