On Edg. Read the excerpt from Dr. Martin Luther King’s “Letter from Birmingham Jail.”

If I sought to answer all the criticisms that cross my desk, my secretaries would have little time for anything other than such correspondence in the course of the day, and I would have no time for constructive work.

What is the author’s purpose for including this sentence?
A. to emphasize the productivity of his daily routine
B. to undermine the significance of his critics’ letter
C. to establish the impressive credentials of his staff
D. to explain the nature of his profession