. 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) (Simplify your answer. Type an ordered pair. Use a comma to separate answers a}; needed.) O B. There'are no points on the graph where the tangent line is horizontal. O c. The tangent line is horizontai at all points of the graph