From the choices presented in parentheses, choose the appropriate term for completing each of the following sentences:

a$.$ A product, sales territory, department, or activity to which costs are traced is called a $($direct cost$,$ cost object$).$

b$.$ Raw materials costs are usually viewed as $($period$,$ product$)$ costs.

c$.$ Factory overhead costs combined with direct labor costs are called $($prime$,$ conversion$)$ costs.

d$.$ The process of developing short$-$term objectives and actions is often referred to as $($operational planning, management by exception$).$

e$.$ A sacrifice made to obtain some benefit is a$($ n