Which of the following is true of direct labor variances? a. The labor efficiency variance measures the difference between what was paid to direct laborers and what should have been paid. b. The labor rate variance measures the difference between the labor hours that were actually used and the labor hours that should have been used. c. The labor rate variance measures the difference between the labor hours that were originally budgeted and the labor hours that should have been used. d. The labor rate and labor efficiency variances will always add up to the total labor variance. e. The labor rate variance measures the difference between the labor hours that were actually used and the labor hours that were originally budgeted.