A control's border is determined by . . . . . . . . property.

The correct answer is: C. BorderStyle

The BorderStyle property of a control determines the style of the control's border. The possible values for the BorderStyle property are:

• None - No border is drawn.
• Fixed3D - A three-dimensional border is drawn.
• FixedSingle - A single-line border is drawn.
• FixedDouble - A double-line border is drawn.
• Sizable - A border is drawn that allows the control to be resized.
• ToolWindow - A border is drawn that is similar to the border of a tool window.
• FixedToolWindow - A border is drawn that is similar to the border of a tool window, but the control cannot be resized.

The BorderStyle property is inherited by child controls. If the BorderStyle property of a parent control is set to a value other than None, the BorderStyle property of its child controls is set to the same value.

The following code snippet shows how to set the BorderStyle property of a button control:

button1.BorderStyle = BorderStyle.Fixed3D;

The following code snippet shows how to get the BorderStyle property of a button control:

BorderStyle borderStyle = button1.BorderStyle;