The correct answer is: A. command button
A command button is a control that is used to execute commands. It is one of the most important controls in a user interface, as it allows users to interact with the application and perform actions. Command buttons are typically rectangular in shape and have a label that describes the action that will be performed when the button is clicked.
A radio button is a control that is used to select one of a set of mutually exclusive options. It is typically represented by a small circle that is filled in when the option is selected. Radio buttons are often used in conjunction with check boxes, which allow users to select multiple options from a set.
A label is a control that is used to provide information to the user. It is typically displayed as a text box or a label that is attached to another control. Labels are often used to provide instructions to the user or to describe the purpose of another control.
A text box is a control that is used to enter text. It is typically represented by a rectangular box that can be used to enter any type of text, including numbers, letters, and symbols. Text boxes are often used to collect data from the user or to provide input to an application.