The China spheres of influence was where certain territories or countries had special access to trade with China. A few nations were under the spheres of influence with China during this time, which granted them free trade and low tariffs. The United States were mostly against this and wanted universal trade for all, disregarding spheres of influence. They wanted no limits on trade with China or any other country, and were worried that by China doing this it would influence other countries into also doing so.
I believe that the answer is D because Yugoslavia was invaded by German troops, they didn't allow them to occupy their country like the other countries.
The issue of comparable worth refers to discrimination in the workplace.