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: Elephants give birth to one calf every ____ to nine years on average.\Question: Choose the right answer from options given a) no b) four c) three d) seven

SOLUTION: b

PROBLEM: Giraffes sleep less than ____ hours a day.\Question: Choose the right answer from options given a) two b) six c) seven d) ten

SOLUTION: a

PROBLEM: Musical usage predates the psychiatric by nearly ____ centuries.\Question: Choose the right answer from options given a) nine b) two c) four d) three

SOLUTION:
d