== Compliant Solution

----
public class BaseClass
{
    public virtual void MyMethod(int i = 1)
    { 
        Console.WriteLine(i);
    }
}

public class DerivedClass : BaseClass
{
    public override void MyMethod(int i = 1)
    {
        // ... 
        base.MyMethod(i);
    }

    static int Main(string[] args) 
    {
        DerivedClass dc = new DerivedClass();
        dc.MyMethod(12);  // prints 12
    }
}
----