3. Using primitive logic gates (i.e., AND, NAND, OR, NOT, NOR), design a 2 X 4 active-low (output) decoder with two active-high and one active-low enables. (10 points) Use a 3-to-8 decoder to implement the function F ABC + A B C . Show all connections and label all inputs and outputs. (10 points) 4. 5. Use an 8x1 multiplexer to implement the function F A C + BC. Show all connections and properly label all inputs and outputs. (10 points) 6. Design a circuit to perform the operation A B or AC where A, B, and C are 4-bit numbers (A3A2A1Ao, B3B2B,Bo, C3C2C,Co). Another input called select (S) is used to decide whether to add B to A or C to A. For example, if select = 1, then the circuit performs A + B while if select = 0 then the circuit performs A C. Use four 2-to-1 multiplexers to implement the selection part of the circuit. Show how A, B, C and the multiplexers are connected. Assume you have the adder circuit, i.e., no need to design the adder. (20 points) Circuit to be Designed Adder