4x1 Multiplexer

module multiplexer(
	input [7:0] a,
	input [7:0] b,
	input [7:0] c,
	input [7:0] d,
	input [1:0] select,
	output reg [7:0] data
);
	always @(*) begin
		case (select)
			2'b00: data <= a;
			2'b01: data <= b;
			2'b10: data <= c;
			2'b11: data <= d;
		endcase
	end
endmodule