The correct answer is: A. State property
The state property of a timer determines whether the timer is running or stopped. When the state property is set to true, the timer is running and will fire at the specified interval. When the state property is set to false, the timer is stopped and will not fire.
The timer control is a graphical control that can be used to create a timer. The timer control has a number of properties that can be used to configure the timer, including the state property.
The enabled property of a control determines whether the control is enabled and can be interacted with. When the enabled property is set to true, the control is enabled and can be interacted with. When the enabled property is set to false, the control is disabled and cannot be interacted with.
The visible property of a control determines whether the control is visible on the form. When the visible property is set to true, the control is visible on the form. When the visible property is set to false, the control is not visible on the form.
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