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: Background radiation comes from ____ sources.\Question: Choose the right answer from options given a) zero b) three c) four d) no

Output: b


Input: Consider Input: Scorpions can live for ____ to seven years.\Question: Choose the right answer from options given a) one b) six c) five d) three

Output: d


Input: Consider Input: Smoking is responsible for more than one out of every ____ deaths in the United States.\Question: Choose the right answer from options given a) three b) six c) five d) ten


Output: c