For the function, nd the points on the graph at which the tangent line is horizontal. If none exist, state that fact. f(x)= 3x2 - 2x+ 4 W Select the correct choice below and, if necessary. ll in the answer box within your choice. 0 A- The point(s) at which the tangent line is horizontal is (are) D. (Simplify your answer. Type an ordered pair. Use a comma to separate answers as needed.) 0 B. There are no points on the graph where the tangent line is horizontal. O C. The tangent line is horizontal at all points of the graph