2. Grade Book tudents who have takezi four tests. The teacher uses the following sign a letter grade to a student, based on the average of his or her A teacher has five who grading scale to as four test scores. Test Score Letter Grade 90-100 80-89 70-79 60-69 0-59 Write a program that uses an array of string objects to hold the five student names, an array of five characters to hold the five students' letter grades, and five arrays of four doubles to hold each student's set of test scores. The program should allow the user to enter each student's name and his or her four test scores. It should then calculate and display each student's average test score and a letter grade based on the average. Input Validation: Do not accept test scores less than 0 or greater than 100. Grade Book Modification Modify the grade book application in Programming Challenge 13 so it drops each s dent's lowest score when determining the test score averages and letter grades