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: Rheumatic fever begins one to ____ weeks after an untreated streptococcal infection.\Question: Choose the right answer from options given a) six b) ten c) two d) zero
Example Output: a

Example Input: Young emus are very vulnerable to disease until they are about ____ months old.\Question: Choose the right answer from options given a) no b) ten c) six d) three
Example Output: d

Example Input: Many people only have one or ____ hives.\Question: Choose the right answer from options given a) four b) two c) six d) one
Example Output:
b