A 5-meter uniform plank of mass 100 kilograms rests on the top of a building with 2 meters extended over the edge as shown. How far can a 50-kilogram person venture past the edge of the building on the plank before the plank just begins to tip?
(A) 0.5 m
(B) 1 m
(C) 1.5 m
( D) 2 m
(E) It is impossible to make the plank tip since the person would have to be more than 2 meters from the edge of the building.