Which of the following statements is correct concerning standard costing and/or variance calculations? A. Variances falling outside of an acceptable range of outcomes require investigation. B. Standards are used at the beginning of the period to budget and at the end of the period to evaluate performance. OC. A favorable quantity (efficiency) variance indicates that a company used less input than expected for the actual level of output. OD. A price (rate) variance calculates the difference between what a company paid and what it expected to pay for its production input. E. All of the above statements are correct.