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').

Example Input: Breast cancer strikes one out of every ____ American women.\Question: Choose the right answer from options given a) one b) nine c) no d) six
Example Output: b

Example Input: Black people are four to ____ times more likely to be stopped and searched.\Question: Choose the right answer from options given a) three b) five c) one d) four
Example Output: b

Example Input: Natural calcium contains ____ isotopes.\Question: Choose the right answer from options given a) one b) eight c) no d) six
Example Output:
d