13.     

Which of the following most logically completes the argument?

United States manufacturers currently produce most of the world's solar-power generators--most of which are exported to Europe.  However, European manufacturers are emerging and probably will ultimately capture much of the European market.  The United States government is funding initiatives intended to encourage use of solar power within the United States.  If these initiatives succeed in increasing the demand for solar-power generators in the United States, United States manufacturers will probably maintain significant production levels, since __________.

(A) some United States manufacturers have been substantially increasing their output over the last several years

(B) the efficiency of solar-power generators in converting energy from the Sun into electric power is not improving as fast as it once did

(C) just as European manufacturers enjoy certain competitive advantages in Europe, so do United States manufacturers in the United States

(D) European governments are currently undertaking initiatives to stimulate the use of solar power within Europe

(E) the current market for solar-power generators in the United States is very limited

答案是C  如果动机成功增加了美国solar-power的需求，美国制造就可以维持大量的生产水平  请NN解释下C~~~ E说市场很有限，好像也可以啊  请NN进一步解释下 谢谢~~