Find the points on the graph of f where the tangent line is horizontal. Order your answers from smallest to largest x. If an answer does not exist, enter DNE.
f(x) = x^3 - 2x^2

A) (x,y) = (,)
B) (x,y) = (,)
C) (x,y) = (,)
D) (x,y) = (,)