1. Start with your completed Retail Price Calculator Application from lab 5. Declare a form level array that will hold multiple (at least 5) retail prices. Modify your application so that it stores each retail price in the array as the user enters multiple wholesale prices with corresponding markup percentages. Add an Exit button to the form that when clicked displays the contents of the array, that is all the retail prices, in a message box before closing the program. 2. Start with your completed Retail Price Calculator Application from the exercise above. Add a method called GetAverage that calculates and returns the average retail price of all the retail prices stored in the array. Add a label to the form that displays the new average after each new retail price is calculated. 3.Copy the folder containing all of the files that contains all of your Retail Price Calculator Application from the exercise above. Rename this folder to remind you that this version will use a list rather than an array. Modify the source code to use a list rather than an array. You want to make sure all retail prices are now stored in a list and that the average is still calculated correctly. This version of the program should not have an array once you are done. It should use the list to hold the retail prices and utilize them to calculate the average. 4. Make another copy of the folder containing all of the files that contains all of your Retail Price Calculator Application that used an array. Rename this folder to remind you that this version will use a rectangular array. Modify your array declaration to be a rectangular array with three columns. The first column will represent a wholesale price, the second column with represent the markup percentage and the third column will represent the retail price. Modify your source code to store the wholesale prices, markup percentages and retail prices in the rectangular array as each retail price is calculated. Modify your GetAverage method to use the rectangular array when calculating the average. Modify your source code to output the wholesale prices, markup percentages and retail prices in the Message Box. Each line of your display should consist of a wholesale price, markup percentage and retail price so that you end up with three columns of information displayed