Final answer:
The VFR transponder code for flying above 12,500 feet is 1200. Codes 7500 and 7700 are for emergencies such as hijacking and general emergencies, respectively, and 2200 is not a standard VFR code.
Step-by-step explanation:
The correct VFR (Visual Flight Rules) transponder code for flying above 12,500 feet in the United States is 1200. This is a standard code used by VFR pilots to indicate they are not receiving ATC (Air Traffic Control) services. It is important to note that the other codes listed have specific emergency purposes: 7500 indicates a hijacking, 7700 signals a general emergency, and 2200 is not typically used as a standard VFR code.