Which force requires contact?
a. the normal force.
b. any fundamental force.
c. gravity.
d. electromagnetic force.

The correct answer would be A.) the normal force.

Explanation:

This is because a "normal force" requires that something touches something else in order for it to move.

There are 4 fundamental forces: gravitation, electromagnetism, weak interaction, and strong interaction. All of these  are non-contact forces. Not B. Gravity is one of the fundamental forces that do not require contact. Not C. The same goes for electromagnetic forces, those don't require contact either. Not D.

The only choice that makes sense is normal force.

Hope this helps,

♥A.W.E.S.W.A.N.♥