What is typically attached to a control point to mark a control card as proof of arrival?

The correct answer is a clipper or control punch. In orienteering and similar navigation activities, a control point is a designated location that participants must find in order to verify their progress along a course. Upon reaching a control point, participants will use a clipper or control punch to mark their control card, which serves as proof of their arrival. This method not only confirms that the participant has visited the control point but also helps maintain the integrity of the navigation course by ensuring that all participants are moving through the designated areas.

Other options, while related to navigation or outdoor activities, do not serve the specific purpose of marking proof of arrival at a control point. A GPS device, for example, can help in locating control points but does not provide physical proof as the control punch does. Maps are essential for navigation and orientation but do not serve as a means of marking control points. Flags might be used to signify the location of a control point, but they do not signify the individual's passage or completion of that point.