Levi's homework is to write a report. He decides to write about his aquarium. He wants to tell readers how to set up an aquarium. How should Levi organize his report?

.by describing the aquarium in detail
.by comparing and contrasting the aquarium
.by explaining problems and giving solutions ​

By explaining problems and giving solutions! this is the best fit because the other two might make sense at a first glance, but only explaining problems and solutions would be an effective way to teach people how to set up an aquarium by giving them examples of what to do and what not to do whereas the others are just him talking about his aquarium.