$7.$ Under direct costing $($DC$),$ fixed manufacturing overhead costs are accounted for as period $$costs$.$ What is the rationale behind this?

$$ A$.$ Fixed manufacturing overhead costs occur regardless of level of production.

$$ B$.$ Fixed manufacturing overhead costs are generally immaterial in amount.

$$ C$.$ Allocation of fixed manufacturing costs are arbitrary at best.

$$ D$.$ Fixed manufacturing costs change as production changes.