Implement switching function of 4 variables H(A,B,C,D)= AB'+BC+A'CD using a 4 to 1 Multiplexer and any number of 2 to 1 multiplexer. One can select any 2 variables (for example, AB or CD) as select inputs of one 4 to 1 multiplexer, then each of the data inputs of the 4 to 1 multiplexer should represent a function of other two variables (CD or AB). The latter functions of two variables should be implemented with 2 to 1 multiplexers.