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Question 2 Use a switch statement to write the following program: The program prompts the user for a letter grade (of type char). The list of valid letter grades is AB D E The program should consider both lower and upper case The program will then display the following messages: For grade 'A': display "Excellent" For grade 'B': display "Good" For Grade 'C': display "Average" For grade" D, or'E' : display "Below Average" For Grade 'F': display "Fail" For any other letter grade entered by users: display "Invalid Grade" 02 Your test plan should include tests for each possible output, invalid input, and lowercase letters