Which of the following statements is correct with regard to direct material variances and/or direct labor variances? A. The standard input ratio for direct materials represents the expected amount of direct material used to produce one unit of output. B. The quantity purchased is used to determine the direct materials price variance. C. The production manager is held responsible for all direct labor variances. D. The direct labor efficiency variance can first be calculated at the point of production. E. All of the above statements are correct.