Among the Reasons Why Ad Valorem Tariffs May Be Preferable

Among the reasons why ad valorem tariffs may be preferable to specific tariffs are:

A) it is easier to set a single ad valorem tariff for a whole category of products that differ in their value than to set specific tariffs for each specific product within that category.
B) specific tariffs would have to be changed frequently as relative prices of different goods change in order to maintain the same level of protection.
C) ad valorem tariffs are more immune to inflation.
D) All of the above.
E) None of the above.