Here is a goal: What is an inexpensive material to use when filling in an unwanted swimming pool.

Which way makes more sense to accomplish this goal?

Select from the following.
- Cover the old cement with a layer of cement, followed by a layer of top soil.
- Cover the old cement with a layer of crushed rock, followed by a layer of top soil.
Cover the old cement with a layer of crushed rock, followed by a layer of top soil.