A rectangular plank of mass `m_(1)` and height a is on a horizontal surface. On the top of it another rectangular plank of mass `m_(2)` and height b is placed. The potential energy of the system is

Options

A. `(m_(1)+m_(2))((a+b))/(2)g`
B. `[(m_(1)+m_(2))/(2)a+m_(2)(b)/(2)]g`
C. `[((m_(1))/(2)+m_(2))a+m_(2)(b)/(2)]g`
D. `[((m_(1))/(2)+m_(2))a+m_(1)(b)/(2)]g`

Answer

C