Which of the following statements is true? The activity variance for a variable expense will usually equal zero. The activity variance for a variable expense will be unfavorable if the actual level of activity is greater than the planned level of activity. The activity variance for a variable expense will be unfavorable if the actual level of activity is less than the planned level of activity. The activity variance for a variable expense can be favorable or unfavorable depending on whether the actual expense incurred is greater than or less than the planned expense.