12. (0 points) Design a 4-bit arithmetic combinational circuit that performs the following operations: Control Inputs M Mo 0 0 0 1 1 1 0 1 if(A/4 = = 0) then S = A + B; else S = A - B if(A S is the 4-bit output of the arithmetic unit (S3S2S1S0). B*8 is the result of performing integer multiplication of the 4-bit number B by 8 (i.e., multiplying B by 2 three times). A/4 is the result of performing integer division of the 4-bit number A by 4 (i.e., dividing A by 2 twice). In this question you are required to design the combinational logic circuit inside the arithmetic unit using the minimum number of the following components: invertors, 4-bit Comparator, 4-bit adders, and 4:1 Multiplexers. You are not allowed to use any other logic components. use 2's complement arithmetic within the design of your circuit once needed. Clearly mark the pins of any component you use by identifying its inputs, outputs, and controls, and explain your solution (No credit without fully explaining the circuit). Hint: multiplication by 2 and division by 2 can be performed by shifting left and shifting right, respectively.