Exercise 2: Add another field called letter to the record which is a character that holds the letter grade of the student. This is based on the average of the grades as follows: test1 and test2 are each worth 30% of the grade while final is worth 40% of the grade. The letter grade is based on a 10 point spread. The code will have to be expanded to find the average. 90-100 80-89 70-79 60-69 0-59 L E S S O N 12 B A B C D F