Concerning the "Universal Functions of Marketing," It Is True That

Concerning the "universal functions of marketing," it is true that:

A) these functions must be performed in all MACRO-marketing systems.
B) these functions can be performed by producers or intermediaries--but not by consumers.
C) from a MICRO viewpoint, every firm must perform all of the functions.
D) responsibility for performing these functions can be shifted and shared--and some functions can be completely eliminated to reduce costs.
E) All of the above are true.