To solve this question, the user needs to understand the concepts of classes, controls, and objects in VB.NET.

Now, let's go through each option and explain why it is right or wrong:

A. a class: This option is incorrect because not everything in VB.NET that has a property or method is necessarily a class. In VB.NET, a class is a blueprint or template for creating objects, but not all objects in VB.NET are classes.

B. a control: This option is incorrect because not everything in VB.NET that has a property or method is necessarily a control. Controls are a specific type of object in VB.NET that are used to interact with the user interface, but there are other types of objects in VB.NET that are not controls.

C. an object: This option is correct. In VB.NET, everything that has a property or method is an object. An object is an instance of a class and can have properties and methods that can be accessed and used.

D. Both a and b: This option is incorrect because it does not cover the case where something in VB.NET has a property or method but is neither a class nor a control.

E. All of the above: This option is incorrect because it does not cover the case where something in VB.NET has a property or method but is neither a class nor a control.

E. All of the above: This option is incorrect because it includes option D, which is incorrect. Not everything in VB.NET that has a property or method is both a class and a control.

Therefore, the correct answer is option C: an object.