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: Centrifugal pumps can usually handle up to about ____ percent by volume of air.\Question: Choose the right answer from options given a) one b) five c) eight d) seven

SOLUTION: b

PROBLEM: Most aphthous ulcers heal in one to ____ weeks.\Question: Choose the right answer from options given a) two b) eight c) one d) seven

SOLUTION: a

PROBLEM: Japan has ____ to four thousand islands.\Question: Choose the right answer from options given a) nine b) no c) seven d) three

SOLUTION:
d