13. Defense Department analysts worry that the ability of the United States to wage a
prolonged war would be seriously endangered if the machine-tool manufacturing base shrinks
further. Before the Defense Department publicly connected this security issue 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 true, 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 too
builders.
B. The Defense Department is only marginally concerned with the effects of foreign
competition on the machine-tool industry.
C. The machine-tool industry encountered difficulty in obtaining governmental protection
against imports on grounds other than defense.
选Ｃ怎么解释啊，谢谢，呵呵， | 
