what happens when the countries with a negative trade balance can't afford to import goods anymore? who does it hurt?

It Hurts the buyers and traders when they can't afford for good items maybe food it depends what they are trading. If they are Negative they either have to trade other traders or they need to buy more goods to trade and sell for possibility better items kind of like scamming like how Railroad Companies would scam farmers and lie about the price to get more money.

It would most likely affect the traders the most

And if they have any buyers it would affect them as well because the traders are negative. (This is all based off what I learn in my classes)

a and b!

dfroos means which is a and b