9. In this prоblem yоu will design а series оf MUX devices. а) Drаw a functional block diagram for a 2-input MUX with active-low tri-state enable (labeled E). Use the following labels: select lines Sa, and inputs Xb (with the normally used subscripts), and output Y. All Sa, Xb, and Y are active-high. b) Draw a functional block diagram for a 4-input MUX with active-high tri-state enable (labeled E). Use the following labels: select lines Sa, and inputs Xb (with the normally used subscripts), and output Y. All Sa, Xb, and Y are active-high. c) Design a truth table for a 6-input MUX with no enable. Use the following labels: select lines Sa, and inputs Xb (with the normally used subscripts), and output Y. All Sa, Xb, and Y are active-high. d) Design a 6-input MUX from part one 2-input MUX and a minimum number of 4-input MUX devices (as drawn in parts a and b) and no other device(s). (If necessary, also use SSI gates for much less credit.) e) Add any single device to add an active-low tri-state enable (labeled E) to the design in part c.