Which of the following is a method for a consumer to exercise their opt-out right?

The method for a consumer to exercise their opt-out right through check-off boxes on relevant forms is correct because these boxes are specifically designed to allow individuals to indicate their preference regarding the sharing of their personal information. By checking these boxes, consumers can explicitly communicate their desire to restrict access to their data by certain entities. This process is a straightforward and commonly accepted practice that ensures consumers have a clear, proactive way to manage their privacy preferences.

Other approaches mentioned may not effectively serve as formal mechanisms for opting out. For example, negotiating directly with third parties can be complex and lacks a standardized process, making it less reliable for consumers seeking to protect their data. Automatic opt-in practices may bypass consumer choice altogether, which contradicts the opt-out right. Lastly, declining future financial opportunities does not provide a formal way to restrict data sharing and may not guarantee that a consumer’s information is kept private, as it primarily pertains to future transactions rather than existing data control. Exploring the check-off boxes on forms reflects a consumer's action to maintain control over their personal information effectively.