Realize the function f(A, B, C, D) = AC + ABD + ACD + ABD.
(a) Use a single 8-to-1 multiplexer with an active low enable and an active high output. Use A, C, and D as the select inputs where A is the most significant and D is the least significant.
(b) Repeat part (a) assuming the multiplexer enable is active high and output is active low.
(c) Use a single 4-to-1 multiplexer with an active low enable and an active high output and a minimum of additional gates. Show the function expansion both algebraically and on a Karnaugh map.