The Relationship of Annual Marketing Effort to Annual Sales Revenue

The relationship of annual marketing effort to annual sales revenue is assumed to be an S-shaped curve because the sales response function shows:

A) an additional $1 million of marketing effort results in a far greater increases of sales revenue in the midrange of the curve than at either end.
B) the point at which total revenue and total cost are equal.
C) that when demand diminishes, production costs rise.
D) decreasing costs as a result of marketing economies of scale.