This graph represents the cost and revenue curves of a firm in a perfectly competitive market.According the graph shown, the firm's most efficient scale of operation is to produce quantity:

The implied growth rate for a country between 1960 and 2010 is 6%. This implies that:

A) the country needed to grow at an average rate of 6% per year between 1960 and 2010 to reach the 2010 level of GDP starting with the 1960 level. B) the country needed to grow by at least 6% in any of the fifty years between 1960 to 2010 to reach the level of GDP in 2010 starting with the 1960 level. C) the growth rate of GDP in the country was above 6% between 1960 to 1990 and above 6% between 1991 and 2010. D) the country needed to grow at rates above 6% per year between 1960 and 2010 to reach the 2010 level of GDP starting from the 1960 level.

As the price level falls, buyers require less money for their purchases and the demand for money falls. A decrease in the demand for money will cause business investment to increase. This is called the _____

a. interest rate effect b. exchange rate effect c. wealth effect d. accelerator effect