Two brothers push on a box from opposite directions. If one brother pushes with a force of 86 N and the other brother pushes with a force of 67 N, what is the magnitude of the net force on the box? A. 67 N ×sin(86°) B. 86 N – 67 N C. ([86 N]2 + [67 N]2)1/2 D. 86 N/cos (67°)