Visual Basic Reference
An OptionButton control displays an option that can be turned on or off.
Usually, OptionButton controls are used in an option group to display options from which the user selects only one. You group OptionButton controls by drawing them inside a container such as a Frame control, a PictureBox control, or a form. To group OptionButton controls in a Frame or PictureBox, draw the Frame or PictureBox first, and then draw the OptionButton controls inside. All OptionButton controls within the same container act as a single group.
While OptionButton controls and CheckBox controls may appear to function similarly, there is an important difference: When a user selects an OptionButton, the other OptionButton controls in the same group are automatically unavailable. In contrast, any number of CheckBox controls can be selected.