For the function, find the points on the graph at which the tangent line is horizontal. If none exist, state that fact. f(x) = 5x2 4x+4 Select the correct choice below and, if necessary, ll in the answer box within your choice. U A- The point(s) at which the tangent line is horizontal is (are) (Simplify your answer. Type an ordered pair. Use a comma to separate answers as needed.) C? B. There are no points on the graph where the tangent line is horizontal. (jg: C. The tangent line is horizontal at all points ofthe graph