The correct answer is A. $9,000.
The sales volume variance is the difference between the actual sales and the budgeted sales for the actual level of activity. It is calculated as follows:
Sales volume variance = (Actual sales – Budgeted sales at actual activity) * Budgeted selling price per unit
In this case, the actual sales are $15,000, the budgeted sales at actual activity are $6,000, and the budgeted selling price per unit is $1. Therefore, the sales volume variance is:
Sales volume variance = ($15,000 – $6,000) * $1 = $9,000
Option B is incorrect because it is the difference between the static budget amount and the flexible budget amount. The static budget amount is based on the budgeted level of activity, while the flexible budget amount is based on the actual level of activity. Therefore, the difference between the two amounts is the sales volume variance.
Option C is incorrect because it is the difference between the flexible budget amount and the actual sales. The flexible budget amount is based on the actual level of activity, while the actual sales are the actual amount of sales that were made. Therefore, the difference between the two amounts is the sales quantity variance.
Option D is incorrect because it is the sum of the sales volume variance and the sales quantity variance. The sales volume variance is the difference between the actual sales and the budgeted sales for the actual level of activity, while the sales quantity variance is the difference between the budgeted sales at actual activity and the actual sales. Therefore, the sum of the two variances is the sales variance.