flat lands many sinkholes rugged peaks long rows of ridges
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Rivers leave behind small pieces of rocks after they flood. These small pieces of rock form a floodplain. Which words best describe a floodplain?
Possibilities:
- flat lands
- many sinkholes
- rugged peaks
- long rows of ridges

flat lands