The Volume Variance Is Nonzero Whenever

The volume variance is nonzero whenever:

A) standard hours allowed for the output of a period differ from the denominator level of activity.
B) actual hours differ from the denominator level of activity.
C) standard hours allowed for the output of a period differ from the actual hours during the period.
D) actual fixed manufacturing overhead costs incurred during a period differ from budgeted fixed manufacturing overhead costs as contained in the flexible budget.