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: Aspiration pneumonia includes ____ syndromes based on the nature of the inoculum.\Question: Choose the right answer from options given a) three b) seven c) eight d) no
Example Output: a

Example Input: Baby elephants are usually dependent on mother s milk for at least ____ years.\Question: Choose the right answer from options given a) six b) three c) two d) seven
Example Output: b

Example Input: Heavy infection can kill up to one in ____ young calves.\Question: Choose the right answer from options given a) four b) nine c) eight d) zero
Example Output:
a