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: Scientists divide bats into ____ groups.\Question: Choose the right answer from options given a) five b) two c) one d) zero

SOLUTION: b

PROBLEM: Most children experience at least one episode by the time they are ____ years old.\Question: Choose the right answer from options given a) eight b) one c) ten d) seven

SOLUTION: d

PROBLEM: Moles breed in late winter or spring and have a gestation period of about ____ to six weeks.\Question: Choose the right answer from options given a) four b) zero c) nine d) no

SOLUTION:
a