Which of the following is true?

A.) The activity variance for revenue will equal zero when the planned level of activity equals the actual level of activity.

B.) The activity variance for revenue will be unfavorable if the actual level of activity is greater than the planned level of activity.

C.) The activity variance for revenue can be favorable or unfavorable depending on whether the actual revenue earned is greater than or less than the revenue expected for the actual level of activity.

D.) The activity variance for revenue can be favorable or unfavorable depending on whether the actual revenue earned is greater than or less than the planned revenue.