4. Design a minimal combinational logic circuit that detects the presence of any of the six illegal code groups in the 8421 standard BCD code by providing a logic-1 output. i. Construct the truth table and simplify the Boolean expression using K-map ii. Construct the logic diagram using basic logic gates that produces minimum hardware requirement 5. A combinational logic circuit has four inputs and one output. The output is 1 if and only if the decimal number represented by the inputs in binary code is a prime number. i. Construct the truth table and simplify the Boolean expression into POS form using K-map. ii. Construct the logic diagram using OR-AND gate network with simplified POS expression iii. Construct the logic diagram using only NOR gates with simplified POS expression