Which of the Following Is Not True of Artificial Variables

Multiple Choice

Which of the following is not true of artificial variables?

A) They have no meaning in a physical sense-nothing more than a computational tool.
B) In all linear programs,they appear in the objective function with a very low cost ($M) .
C) They are usually used with ≥ constraints.
D) They are usually used with = constraints.
E) None of the above