$20.$ a$)$ What decision do switches have to make when a frame arrives? b$)$ What is this decision called? c$)$ How do they make this decision? d$)$ Does an individual switch know the frame$$s entire path through a switched single network? e$)$ Are frames addressed to the DLL addresses of a switch or the DLL addresses of a destination host? $($The answer is not in the text.$)$