2.20 A 4-bit binary number is applied to a circuit on four lines D, C, B, and A. The circuit has a single output, F, which is true if the number is in the range 3 to 12, inclusive. Draw a truth table for this problem and obtain a simplified expression for F in terms of the inputs. Implement the circuit (a) in terms of NAND gates only (b) in terms of NOR gates only