Table: Profit Margins This Table Shows That Silver, Copper

Multiple Choice

Table: Profit Margins This table shows that silver, copper, and gold were some of the most profitable industries in July 2011. (For each dollar of sales, profit for these industries is 35.1, 23.5, and 22.0 cents, respectively.) According to the elimination principle, what do you expect to happen to these profit margins in the long run?

A) Profit margins will increase because of increased entry.
B) Profit margins will increase because of increased exit.
C) Profit margins will decrease because of increased entry.
D) Profit margins will decrease because of increased exit.