请各位大牛们帮我解道题吧~

og 第十版的第十三题，

Defence Department analysts worry that the ability of the US to wage a prolonged war would be seriously endangered if the machine-tool manufacturing base shrinks further .Before the Defence Deparement publicly connected this security with the import quota issue,however,the machine-tool industry raised the national security issue in its petition for import quotas.

Which of the following ,if ture ,contributes most to an explanation of the machine-tool industry's raising the issue above regarding national security?

A.When the aircraft industries retooled ,they provided,a large amount of work for tool builders

B.The Defence Department is only marginally concerned with the effects of foreign competition on the machine-tool industry

C.The machinr-tool industry encountered difficulty in obtaining governmental protection against imports on grounds other than defence

D.A few weapons imported for defence consisit of parts that do not require extensive machining

E,Several federal government programs have been designed which will wnable domestic machine-tool manufacturing firms to compete successfully with foreign toolmakers.

谢谢