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

SOLUTION: a

PROBLEM: Natural tellurium consists of ____ isotopes.\Question: Choose the right answer from options given a) six b) seven c) eight d) one

SOLUTION: c

PROBLEM: Muscle burns ____ times the calories that fat does.\Question: Choose the right answer from options given a) one b) nine c) eight d) no

SOLUTION:
c