The correct answer is D. Option group button.
An option group is a control that allows users to select one of a set of mutually exclusive options. The options are represented by option buttons, which are small circles that are either filled in or empty to indicate whether the option is selected. The option group frame is a rectangular border that surrounds the option buttons and groups them together. The option group label is a text box that displays the name of the option group.
Option group buttons are not a part of an option group because they are not necessary to create or use an option group. Option buttons can be added to an option group, but they are not required.