Which of the following statements concerning performance reports is incorrect? O A. The master budget and the flexible budget use the same cost behavior equations to calculate budgeted expenses. B. An unfavorable sales revenue flexible budget variance would indicate that the actual sales price was higher than the sales price used in the master budget. C. All material flexible budget variances should be investigated. D. The activity level used to populate the flexible budget is based on the actual "units." E. The master budget variance is equal to the sum of the volume variance plus the flexible budget variance