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: Astronauts sleep only ____ hours each night, on average.\Question: Choose the right answer from options given a) six b) one c) four d) seven
Example Output: a

Example Input: Stringers consist of ____ narrow pieces of wood glued together.\Question: Choose the right answer from options given a) ten b) three c) five d) seven
Example Output: b

Example Input: Most babies say their first words between ____ and eleven months of age.\Question: Choose the right answer from options given a) ten b) one c) zero d) no
Example Output:
a