Many Studies Dealing with Incomes Earned in the Business Community

Many studies dealing with incomes earned in the business community tell us that:

A) salespeople earn significantly higher incomes than most other workers in the business community.
B) salespeople earn slightly less than other workers in the business community.
C) salespeople earn about the same income as other persons in the business community.
D) there are no relevant studies that link income and the salesperson.
E) salespeople earn significantly lower incomes than other workers in the business community.