Programming Assignment 4: Chapter 5 Write, compile, and test a program in C# called DisplaySales. Mark, Jennifer, and Robin are three salespeople. Write a program in C# called DisplaySales that asks the user for a salesperson initial (M, J, R) - Either uppercase or lowercase is accepted. As long as the user hasn't entered the letter Z, continue asking the amount of a sale. Issue an error message for invalid initials. Keep a running total of the amounts sold by each salesperson. In the end, when the user types Z, display each salesperson's total, the final total for all sales, and the name of the salesperson with the highest total. Formatting should be included. What does X signals? How would your code change if I asked you to enter a negative number instead of Z? I need to see the outline of the change/code..