What force, in newtons, is required to keep the object in the picture below at rest?

18 N, 18 N, 12 N, ?

A.
0 N

B.
12 N

C.
18 N

D.
48 N

A. 0 N

Since the object is at rest, the net force acting on it must be zero. Therefore, the force required to keep the object at rest is 0 N.