The key differences between the traditional flexible budget and the activity-based flexible budget are a. the traditional should be used when a significant portion of the costs vary with cost drivers other than units of production b. traditional flexible budgeting is dramatically increasing in popularity c. some manufacturing costs that are fixed with respect to unit are variable with respect to cost drivers, and other than units, used for an activity-based flexible budget d. the larger the company, the more likely the activity-based flexible budget will not be used