(40 pts) 3. Using Karnaugh maps, find a minimal product-of-sums expression for each of the following logic functions. List all the essential O-cells, and mark them with an "*" in the map. Draw a two-level logic diagram using NOR-NOR logic. (a) F (A, B, C, D) = (A+++D) (A+B+D)(+B+D) A+B+C) (b) F(W, X, Y, Z) = (4, 5, 6, 11, 13, 14, 15) (c) F(X, Y, Z) = (1, 2, 6, 7) (d) F (W, X, Y, Z) = + (1, 3, 8, 10, 15) (10 pts) 4. Implement the following Boolean function F, together with the don't care conditions d. using no more than two NOR gates: F(A, B, C, D) = (2, 4, 10, 12, 14.) d(A, B, C, D) - (0,1,5,8) Assume that both the normal and complement inputs are available