1. In this task first you need to use the concept of derived classes, then the access modifiers.
2. We use the : symbol to specify the parent class in the definition of a child (derived) class.
3. Recall which access modifier is appropriate for the name field to hide it from the outside of the class but make it accessible from the child classes.

using System;

public class Person
{
    // Field to store the name
    protected string name;
}

public class Student : Person
{

    public Student(string name)
    {
        this.name = name;
    }

    public void Study()
    {
        Console.WriteLine($"{name} is studying.");
    }
}

public class Teacher : Person
{
    public Teacher(string name)
    {
        this.name = name;
    }

    public void Teach()
    {
        Console.WriteLine($"{name} is teaching.");
    }
}

public class Program
{
    public static void Main(string[] args)
    {
        Teacher t = new Teacher("Hannah");
        Student s = new Student("Mark");

        t.Teach();
        s.Study();
    }
}