Which of the following statement is correct concerning standard costing and/or variance calculations? O A. A favorable quantity (efficiency) variance indicates that a company used more input than allowed for the actual level of output. OB. A price (rate) variance calculates the difference between what a company paid and what it expected to pay for its production output. O c. Standards are used at the beginning of the period to budget and at the end of the period to evaluate performance. O D. Variances falling outside of an acceptable range of outcomes do not require investigation. O E. Quantity (efficiency) standards represent the expected cost per unit of input