The Predominant Response Function for Advertising Is Often Concave, but When

Multiple Choice

The predominant response function for advertising is often concave, but when it is S-shaped, ________.

A) sales are flat, and advertising does not generate any sales impact
B) any increase in advertising spending results in a proportionally positive increase in sales
C) any increase in advertising spending results in a proportionally negative decrease in sales
D) some positive amount of advertising is necessary to generate any sales impact, but sales increases eventually flatten out
E) advertising is not necessary to generate any sales impact