New to OOP and C#

Class C would have to have to have access to the instance of class B somehow. Either by having and instance of C as a member of class B, or by exposing the member of B that you want to access. This might be easier if you used "actual" classes, I always like to do shapes... like, Shape, Circle, and Sphere where Shape is a base class, Circle inherits from Shape, and Sphere inherits from Circle.

As for your second question, how the construction chain is executed depends on where you have intialized your variables in code. It might be easier to explain if you code up something and ask questions about it :)