Which of the following natural features would likely exist in a densely populated area of the world?
a.)subzero temperatures
b.)fertile farmland
c.)mountainous regions
d.)swamp marsh

I am absolutely sure that  the following natural feature which would likely exist in a densely populated area of the world is being revealed by the option : B.)fertile farmland. I consider this option as a correct one because this is the most necessary and useful point for sustaining a large populations.
Do hope it will help you!
Regards.

Answerequatorial guinea,gabon, and western sahara;

There is no map, maybe give the link, it may be b