Choose an example of how a manager can increase variable costs while decreasing fixed costs.

A$.$ Subcontracting a component to a supplier on a per$-$unit basis to avoid purchasing a machine with a high fixed depreciation cost.

B$.$ Hiring a subcontractor to do repairs on an annual retainer basis rather than on a per$-$visit basis.

C$.$ Changing a sales force compensation plan from a percent of sales dollars to a fixed salary.

D$.$ None of the above.