A 10 kg block is place on top of the 20 kg block as shown. The system of two block can move on a horizontal frictionless surface. The coefficient of static friction between the blocks is 0.6. If a horizontal 150 N force is applied to the 20 kg block and the top block doesn’t slide on the bottom block, what is the magnitude of the horizontal force that the 10 kg block exerts on the 20 kg block?
(A) 10 N (B) 20 N (C) 30 N (D) 50 N (E) 60 N