3. (2.5pt) An even parity checker takes multiple inputs (e.g. 2 inputs X and Xo), and produces 1bit of output D, such that when there are even number of 1s in the input (e.g. for two inputs, X = X = 1, or X = Xo = 0), D = 0. Otherwise D = 1. A. Draw the truth table of a 2bit even parity checker. You do NOT need to draw the circuit diagram for 3A. (1pt) O B. Use the 2bit even parity checker as functional block, draw the circuit diagram of a 4bit even parity checker. Hint: you need to use three 2bit even parity checkers (1.5pt)