Which of the following statements regarding a linear cost function is TRUE?

A$.$ The slope coefficient of a mixed cost line intersects the vertical axis at zero.

B$.$ It is easier to identify a single measure of benefit in a more heterogeneous cost pool.

C$.$ A linear cost function for manufacturing overhead can be graphed when their is a cause$-$and effect relationship between the level of activity and the costs related to that level of activity.

D$.$ When there are only fixed costs, total material casts increase as the number of units produced increases:

E$.$ The relationship between the cost driver and the fixed cost is represented by the cost$-$benefit relationship.