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: Calves remain hidden for much of the time, and are weaned by ____ months of age.\Question: Choose the right answer from options given a) six b) three c) eight d) one
Example Output: b

Example Input: Fish have a two-chambered heart while mammals and birds have ____ chambered hearts.\Question: Choose the right answer from options given a) nine b) five c) four d) one
Example Output:
c