A $4-$kg block moves down a rough $37$ incline a distance of $5m$ from point $A$ to point $B.$ As shown in the

figure below, a horizontal force of magnitude $F=10N$ is applied to the block between these two points.

The kinetic energy of the block at point A is $10J$ and the kinetic energy of the block at point B is $20J.$

What is the increase in internal energy of the block$-$incline$-$Earth system due to friction?

A$.40J$

B$.80J$

C$.60J$

D$.50J$

E$.,70J$