Write a program called grade_need. c that calcualtes the minimum percent needed on the final to achieve the desired grade. If the desired grade cannot be achieved because the person cannot score low or high enough on the final to get the desired grade, your program should tell them so. Grade Minimum Percent Needed A 90% B 80% C 70% D 60% F 0% Requirements Your program should be able to accept both lowercase and uppercase letters for the letter grade desired Assumptions Input is NOT guarenteed to be valid Some examples of improprer input are Incorrectlly formatted input Incorrect letter grades desired If invalid input is received, your program should report it and terminate You'll find the exit function in stdlib. h for doing this. Make sure to only use 0 with exit and no other value. Wait until we cover how to handle invalid input in class before dealing with this part of the problem