Is Relatively Easy to Measure the Incremental Cost of a New

is relatively easy to measure the incremental cost of a new advertising campaign; what is not as easy is

A) measuring the extra fixed cost involved.
B) measuring the extra variable cost involved.
C) measuring the incremental revenue generated by the new advertising campaign.
D) determining whether customers who stop buying the product are reacting negatively to the advertisement or to some other aspect of the product itself.
E) determining what percentage of the ad-generated revenue should be reinvested into additional advertisements of the same form.