Which of these partly accounts for the long-term growth in production in the U.S.economy?

A) An increase in government spending
B) An increase in the availability of resources
C) A reduction in federal taxes
D) A gradual but consistent increase in the price level
E) A general optimism about the future and the pioneering spirit of America

An increase in the availability of resources such as labor, capital, and technology has allowed for sustained long-term growth in production in the U.S. economy. This has led to increased efficiency and productivity, which in turn has contributed to economic growth.

Answer: E
A general optimism about the future and the pioneering spirit of America has also played a role in the long-term growth of the U.S. economy, as entrepreneurs and businesses have been motivated to take risks and innovate, leading to economic growth and development. However, this is not the only factor and is less significant than an increase in resources.