how to check if a dialog choice inside another dialog choice is selected?

Hello! I want to make a trader N.P.C that first asks if the player needs a bow or a sword then asks what type of that weapon he wants (example: the player chose to have a sword, now the N.P.C asks him if he wants a snow sword or fire sword), then after the player chooses I want to check which type of weapon he chose so I will give him, how to make this?