How might an author develop a key concept about the benefits of recycling?

by instructing the reader to research recycling in their community
by instructing the reader to research recycling in their community

by detailing which neighborhoods recycle properly and which do not
by detailing which neighborhoods recycle properly and which do not

A chart showing what kinds of materials get recycled would not develop the key concept about how recycling is beneficial.
A chart showing what kinds of materials get recycled would not develop the key concept about how recycling is beneficial.

by providing information on the environmental impacts of recycling

by providing information on the environmental impacts of recycling