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: Beer is made from fermented grains and has an alcohol content of ____ to six percent.\Question: Choose the right answer from options given a) zero b) three c) two d) ten
Example Output: b

Example Input: Most infected persons have ____ symptoms of disease.\Question: Choose the right answer from options given a) six b) no c) three d) one
Example Output: b

Example Input: Disaccharides are ____ monosaccharides linked together.\Question: Choose the right answer from options given a) ten b) one c) six d) two
Example Output:
d