Relationship of Annual Marketing Effort to Annual Sales Revenue Is

relationship of annual marketing effort to annual sales revenue is assumed to be __________ of the sales response function.

A) a horizontal straight line, where sales revenues stay the same regardless of the marketing effort
B) a U-shaped curve, where sales revenues are at a maximum at either end
C) an upside-down U-shaped curve, where sales revenues are at a maximum in the middle
D) a S-shaped curve, which shows that an additional marketing effort in the midrange of the curve results in far greater increases of sales revenue than at either end of the curve
E) a rising straight line, where sales revenue continuously rises as the marketing effort rises