The correct answer is: A. Combo Box.
A combo box is a graphical control element that allows the user to select one or more items from a list. The list of items is displayed in a drop-down list when the user clicks on the combo box.
A combo list is a list of items that is displayed in a list box. The user can select one or more items from the list box.
A check box is a graphical control element that allows the user to select one or more options. The options are displayed as small boxes that can be checked or unchecked.
A radio button is a graphical control element that allows the user to select one option from a group of options. The options are displayed as small circles that can be selected or deselected.
Here is a diagram of a combo box:
Here is a diagram of a combo list:
Here is a diagram of a check box:
Here is a diagram of a radio button: