I don't know how C) fits in the narrative. I think we could flush this out a little more.

Global economies are linked. If China isn't doing well, there's a risk that could spill over into other countries (point D), and that includes the US.

Are we saying that the US is doing well, but China is doing poorly because, all else equal, if the China-US trade discussions do not end well, it harms China more than it harms the US? It would certainly hurt both economies. Costs for goods would rise in the US. US Consumers buy less, consumer confidence slides, 70% of economic activity is consumer spending, etc.