4. (2 pts) Design a circuit that takes two 4bit numbers A and B as input and produces output depending on the two select inputs so and s according to the following table. You can use one 2x1 Multiplexer, 4bit adder and Logic gates. i. So $ = 00: A+B (A plus B) ii. So S1 = 01: AB (A minus B) iii. So S = 10: iv. So S = 11: AB AB' (A and B (bitwise)) (A and B' (bitwise))