SG&A are always period costs, whether fixed or variable.

All variable costs, whether they are product costs or period costs, are included in arriving at contribution margin.  Do not confuse contribution margin (sales less all variable costs) with gross margin, which expenses all product costs as the inventory is sold.

Gross margin:
absorption: sales - sum(DM, DL, variable and fixed OH)
direct/variable costing: sales - sum(DM, DL, variable OH)

Good luck today!  Let us know how your exam goes.