下列语句书写是合法的，并且描述了一个四路选通器。assign Mux = (S = = 0)? A : 'bz;assign Mux = (S = = 1)? B : 'bz;assign Mux = (S = = 2)? C : 'bz;assign Mux = (S = = 3)? D : 'bz;