Design and build a combinational logic circuit with four inputs, labeled W, X, Y, and Z and one output, labeled BCD. The output is to be 1 if the input is a valid BCD code. If any other input combination occurs, the output should be 0. Implement the circuit using: a. Any gates available in the lab. b. One 74x151 and a single inverter. c. One 74x138, one OR gate and one NAND gate.