The logic inputs would be the 4 logic sources from the left(A,B,C,D),and the 2 of the bottom are the selection keys, according to the combination of the selection keys the output will be A,B,C or D.
The number of components is high because I had to use multiple 2 input logic components instead of 3 or 4 input ones.
It's useful to understand how a MUX works,as you can see the logic path with colors
