What will be the output of the following code?

What will be the output of the following code?

class Base {
    public virtual string GetMessage() => "Base";
}
class Derived : Base {
    public override string GetMessage() => "Derived";
}
class Program {
    static void Main() {
        Base obj = new Derived();
        System.Console.WriteLine(obj.GetMessage());
    }
}