In Order to Keep Small Rocks from Falling onto a Road,you

In order to keep small rocks from falling onto a road,you would

A) install pipes to drain water out of the slope above the road.
B) install rock bolts to firmly attach the rocks to the slope.
C) install metal mesh over the slope to intercept small rocks.
D) remove all the small rocks from the slope above the road.
E) remove any trees from the slope above the road.