Please solve correctly with detailed and proper reasoning

As a new digital designer, your job is to develop a calculator for a number system. In this particular task, given a 4-bit number Y3Y2Y1Y0 in a 2's complement system, design a circuit that takes the absolute value of this number and outputs Z3Z2Z1Z0. Therefore, if the input is positive the output is the same as the input. If the input is negative, the output is positive. As an example, you may use IN3, IN2, IN1, INO on the DEB to represent Y3Y2Y1Y0 and OUT3, OUT2, OUT1, and OUTO on the DEB to represent Z3Z2Z1Z0. 1) Knowing about the 2 's complement number system, how can you implement digit Z3 immediately? Explain your reasoning. 2) Assume that the input combination Y3Y2Y1Y0=1000 never shows up and is irrelevant. Why is it useful or practical to make this assumption? What is the most efficient way to handle that condition