GMAT Critical Reasoning (CR) | The recent decline in the value of the dollar was triggered

Hi guys,

Please help me rule out option B. My reasoning is that:
Huge budget deficit--> prediction of slow economy leads to value decline

If Huge budget deficit doesn't cause the economy slowdown, the prediction of slow economy must come from a different reason, not from huge budget deficit. Therefore, it weakens the argument.

I know B is wrong, but someone please help fix my reasoning?I don't understand why people say B is not relevant