With Today's Technology,wind Energy Could Only Meet 30- 40% of Total

With today's technology,wind energy could only meet 30- 40% of total electricity needs in the United States.All of the following are reasons why wind energy cannot meet a greater portion of our energy needs except:

A) We cannot efficiently move electricity across a large grid from windy areas to distant areas where there are no wind farms.
B) We have no efficient way of storing excess amounts of electricity produced when it is windy.
C) Wind turbines are only 30- 40% efficient at converting wind energy into electricity.
D) Wind is an intermittent resource and may not be blowing when we need the electricity.