>1)What type of relation should I use? Agregation or Asociation?
I would say Association or even better Dependency. Dependencies relationships are used when you want to show one thing using another. In you case, the business class will use the data class.

>2)I derived a concrete class cBusiness and cData, the relation is between concrete class or abstract class?
I would say that you need to express the dependency relationship in the abstract class. However, I don't think any of the modeling tools will carry this relationship when you draw the concrete classes. You may need to redraw the dependency between concrete classes on each individual class diagram.

Now that I think of it, this redrawing probably makes sence since your cBusinessA will depend on cDataA but not on cDataB.

Hope that helps.