Design an Essay class that extends the GradedActivity class presented in this chapter. The Essay class should determine the grade a student receives for an essay. The student’s essay score can be up...

Design an Essay class that extends the GradedActivity class presented in this chapter. The Essay class should determine the grade a student receives for an essay. The student’s essay score can be up to 100 and is determined in the following manner:
Grammar: 30 points
Spelling: 20 points
Correct length: 20 points
Content: 30 points
Demonstrate the class in a simple program.