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: Traditional neon electrifies the inert gas from ____ directions.\Question: Choose the right answer from options given a) two b) nine c) one d) six
Example Output: a

Example Input: Coccidiosis usually occurs from ____ weeks of age.\Question: Choose the right answer from options given a) zero b) no c) three d) eight
Example Output: c

Example Input: Scientists believe three out of every ____ breast cancers are hormone responsive.\Question: Choose the right answer from options given a) two b) seven c) ten d) five
Example Output:
d