Two forces (4n and 3n) pull to the left while a 12n force pulls to the right. what is the net force?

Call the positive direction the one that points to the right.

                   negative force <===      ===> positive force

Then the forces are +12n, -4n, and -3n.

The net force is their sum:  (+12n - 4n - 3n) = +5 n  .

                                             (5 newtons, pointing to the right) .

The correct answer is c. hope this