When a Newspaper Editor Talks About "The Wall," He or She

When a newspaper editor talks about "The Wall," he or she is referring to:

A) the difference between veteran and cub reporters.
B) the formal separation of the newspaper's news staff and business department.
C) how difficult it is to access certain information.
D) the separation of classified advertising from the other advertising that commonly appear in newspapers.
E) the lowest possible ad placement rate in the newspaper.