All of the Following Statements Are Correct Except

Multiple Choice

All of the following statements are correct except

A) knowledge about one process spills over into other segments of the economy.
B) additional knowledge makes people more productive,and there seems to be no tendency for the additional productivity from additional knowledge to diminish.
C) knowledge has no external benefit.
D) knowledge might be an exception to the principle of diminishing marginal benefit.
E) it is necessary to use public policies to ensure that those who develop new ideas have incentives to encourage an efficient level of effort.