D. Mars.
Hope this helps, if not, comment below please!!!
The tropical forest covers most of the land.
The width is 60 because since the length is 80 you can add 80 and 80 and get 160.
When you get 160 you subtract it from 280 the perimeter.
280-160=120
120÷2=60
60 is the width.
Hope it helps.