Firms' Profits or Production Do Not Increase in the Long

Multiple Choice

Firms' profits or production do not increase in the long run because:

A) some factors of production are fixed in the long run.
B) all the factors of production are variable in the long run.
C) changes in factor costs completely offset any change in the price level.
D) there exists an excess capacity in the economy in the long run.
E) factor costs remain fixed in the long run.