Rates of Change in Linear and Quadratic Functions Quiz Submit X 5 6 2 of 6 The function f is defined for all real values of c. For a constant a, the average rate of change of f from a = a to x = a + 1 is given by the expression 2a + 1. Which of the following statements is true? 2 A The average rate of change of f over consecutive equal-length input-value intervals is positive, so the graph of f could be a line with a positive slope. B The average rate of change of f over consecutive equal-length input-value intervals is positive, so the graph of f could be a parabola that opens up. C The average rate of change of f over consecutive equal-length input-value intervals is increasing at a constant rate, so the graph of f could be a line with a positive slope. D The average rate of change of f over consecutive equal-length input-value intervals is increasing at a constant rate, so the graph of f could be a parabola that opens up