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: National immunization vaccinates all children under ____ against polio.\Question: Choose the right answer from options given a) zero b) four c) ten d) five

SOLUTION: b

PROBLEM: Most roots require from ____ to six weeks to dry sufficiently to be safe.\Question: Choose the right answer from options given a) two b) four c) eight d) three

SOLUTION: d

PROBLEM: Most women have ____ symptoms of heart disease with mitral valve prolapse.\Question: Choose the right answer from options given a) three b) no c) five d) ten

SOLUTION:
b