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').

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
b

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

Most portable extinguishers discharge completely in as few as ____ seconds.\Question: Choose the right answer from options given a) three b) one c) eight d) ten

c