请教一道逻辑真题

春天的花儿会开

Editorial in Krenlandian Newspaper:
Krenland’s steelmakers are losing domestic sales because of lower-priced imports, in many cases because foreign governments subsidize their steel industries in ways that are banned by international treaties. But whatever the cause, the cost is ultimately going to be jobs in Krenland’s steel industry. Therefore, it would protect not only steel companies but also industrial employment in Krenland if our government took measures to reduce cheap steel imports.
Which of the following, if true, most seriously weakens the editorial’s argument?
A. Because steel from Krenland is rarely competitive in international markets, only a
very small portion of Krenlandian steelmakers’ revenue comes from exports.
B. The international treaties that some governments are violating by giving subsidies
to steelmakers do not specify any penalties for such violations.
C. For many Krenlandian manufacturers who face severe international competition
in both domestic and export markets, steel constitutes a significant part of their
raw material costs.
D. Because of advances in order-taking, shipping, and inventory systems, the cost of
shipping steel from foreign producers to Krenland has fallen considerably in
recent years.
E. Wages paid to workers in the steel industry in Krenland differ significantly from
wages paid to workers in many of the countries that export steel to Krenland.
the key:C
没看出来C是如何削弱的，谢谢

kathy72

C说K国的制造商在国际市场的竞争力依赖于其原材料钢的成本. 也就是说, 如果不让国外低成本的钢进口, 国内的制造商的成本上升, 一样会削弱K国的出口.

注意这里的制造商(manufacturer)和文中的钢铁厂(steelmaker)指的不是同一种企业.