Which One of the Following Presents the Correct Formula for the Sales

Which one of the following presents the correct formula for the sales price variance calculation?

A) (Actual sales in units - budgeted sales in units) x (standard selling price per unit - standard variable costs per unit) .
B) (Actual unit selling price - standard unit selling price) x budgeted sales in units.
C) (Actual unit selling price - standard unit selling price) x actual units sold.
D) (Actual unit selling price - standard unit selling price) x (actual units sold - budgeted sales units) .