(A) Write the truth table for the most significant block of an n-bit ripple carry adder. Inputs should be the MSB operands Xn-1, Yn-1, and carry-in bit Cn-1. Outputs are the sum bit Sn-1 and carry-out bit Cn.

(B) Add a new variable to this table (V) that indicates overflow according to the comparison of Xn-1, Yn-1, and Sn-1

(C) Prove that V = Cn-1 XOR Cn