请教GWD 9-28

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?

1. Because steel from Krenland is rarely competitive in international markets, only a very small portion of Krenlandian steelmakers’ revenue comes from exports.

2. The international treaties that some governments are violating by giving subsidies to steelmakers do not specify any penalties for such violations.

3. 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.

4. 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.

5. 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.

答案是C，原文我知道什么意思，但是怎么推出削弱呢？谢谢！

结论是:如果政府能够采取措施减少便宜的钢铁进口,就不仅能保护钢铁公司还能保护Krenland的产业就业率(industrialemployment),这里的就业率不仅包括钢铁业的还包括其他制造业的。对于其他以钢为原材料(构成其主要成本)的企业,如果失去低价钢铁的来源,就会成本上升,降低国内和国际竞争力，可能会提高失业率。因此是削弱。