Deep Copy vs Shallow Copy in C#

using System;

namespace Delegates
{
    class Program
    {
        static void Main(string[] args)
        {
            var firstStudent = new Student("Gosho Goshev", 1000, new Grade ("Good", 4 ));
            var secondStudent = new Student("Ana Ivanova", 2000, new Grade("Very Good", 5));

            //secondStudent = firstStudent.ShallowCopy();
            //secondStudent.Grade.Name = "Exellent";
            //secondStudent.Grade.Value = 6;
            // Console.WriteLine($"{firstStudent.Name} {firstStudent.ID} {firstStudent.Grade.Value}"); // Gosho Ivanov, 1000, but grade is also 6 like grade in secondStudent

            // With Deep Copy we can copy all of the value types and we create new references in the secondStudent
            secondStudent = firstStudent.DeepCopy();
            secondStudent.Grade.Name = "Exellent";
            secondStudent.Grade.Value = 6;
            Console.WriteLine($"{firstStudent.Name} {firstStudent.ID} {firstStudent.Grade.Value}"); // // Gosho Ivanov, 1000, 4 is not changed after the changes in secondStudent

        }

        public class Student
        {
            public Student(string name, int iD, Grade grade)
            {
                this.Name = name;
                this.ID = iD;
                this.Grade = grade;
            }

            public string Name { get; set; }
            public int ID { get; set; }
            public Grade Grade { get; set; }


            public Student ShallowCopy()
            {
                Student tempObject = (Student) this.MemberwiseClone();
                return tempObject;
            }

            public Student DeepCopy()
            {
                Grade gradeCopy = new Grade(this.Grade.Name, this.Grade.Value);
                Student newStudent = new Student(this.Name, this.ID, gradeCopy); // we have a constructor
                return newStudent;
            }

        }

    }

    public class Grade
    {
        public Grade(string name, int value)
        {
            this.Name = name;
            this.Value = value;
        }

        public string Name { get; set; }
        public int Value { get; set; }
    }
}