To solve this question, the user needs to have a basic understanding of VB.NET controls and objects.

In VB.NET, a control is an object that can be added to a form to create an interactive user interface.

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

A. Button: This option is correct. A button in VB.NET is an example of an object. It is a control that can be added to a form and has properties, methods, and events that can be accessed and manipulated in code.

B. Label: This option is correct. A label in VB.NET is an example of an object. It is a control that can be added to a form and has properties, methods, and events that can be accessed and manipulated in code.

C. Textbox: This option is correct. A textbox in VB.NET is an example of an object. It is a control that can be added to a form and has properties, methods, and events that can be accessed and manipulated in code.

D. Both a and b: This option is incorrect. While both a button and a label are examples of objects, a textbox is also an example of an object.

E. All of the above: This option is correct. All three controls - button, label, and textbox - are examples of objects in VB.NET.

The Answer is: E