Question

Which unit of measurement is best to measure the amount of water in a swimming pool?
a. mililiter
b. kiloliter
c. centiliter
d. kilometer

Answer 1

kiloliters is your answer

Answer 2

I would eliminate the answers with -meter in it because that measure length or depth. That leaves you with B and C. Then classify what the prefixes kilo- and centi- mean 
Kilo meaning 1000
Centi meaning 100. 
I would go with C. Centiliter