12. (6 points) A parity bit is an extra bit included in a binary message to detect errors that occur during transmission of the message. It is set to either 1 or 0 to make the total number of 1's either even or odd. In the case of even parity, if the total number of 1's is odd, the parity bit is set to 1, and if it is even, the parity bit is set to 0. Assume that a 4-bit binary message is to be transmitted with an even parity bit. Consider an Even Parity Generator circuit for this purpose, which has four inputs (A, B, C, D) and one output for the parity bit P. (a) (2 points) Construct a truth table for this circuit in terms of its inputs and outputs. (b) (2 points) Find the minterm expansion for the output. (c) (2 points) Find the maxterm expansion for the output.