A Job Description for a Sales Position

A job description for a sales position

A) should be detailed enough that it lists the specific tasks to be performed.
B) should be in writing, but should be quite general so that it doesn't reduce the sales manager's flexibility in assigning jobs.
C) should look pretty much the same from one company to another.
D) is not very useful, since the job is always changing.
E) all of the above.