Final answer:
New private class level variables cannot be added to a subclass.
Step-by-step explanation:
When subclassing in object-oriented programming, new public class level variables, new public methods, and new private methods can be added to the subclass. However, new private class level variables cannot be added to a subclass as they are not inherited from the superclass. Private variables are only accessible within the class they are declared in and cannot be accessed or modified by subclasses