Enthuware

This is not the right use of UML... your image depicts dependencies, you want to use the right connectors.

-- Robert

I don't see anything wrong with it. Specially when the question does not say that it is UML. It is just an image that is trying to describe the relationship, which is also described in words in the question. i.e. (B1 and B2 are subclasses of A and C1, C2 are subclasses of B1).

HTH,
Paul.

I think it is better to use the right connector as you suggest. This has now been fixed.

thank you for your feedback!