Consider the graph to the right. Explain the idea of a critical value. Then determine which x-values are YA critical values, and state why. X1 X2 X3 X4X5 X6*7X8*g X10 * . . . What is the idea of a critical value? O A. Critical values are x-values where relative extrema may occur. O B. Critical values are y-values where relative extrema may occur. O C. Critical values are x-values where relative extrema occur. O D. Critical values are the y-values of relative extrema