Which of the Following Statements Is Not Correct

Which of the following statements is not correct?

A) Price variance measures how well a business keeps unit prices of materials and labor within standards.
B) An efficiency or quantity variance measures how well a business uses its materials or direct labor hours.
C) A price variance is the difference between actual and standard prices of an input, multiplied by the standard quantity of the input.
D) A quantity variance is the difference between actual and standard quantity of an input, multiplied by the actual quantity of the input.