Final answer:
CFC-11 has the highest ODP rating among refrigerants.
Step-by-step explanation:
The highest ODP (Ozone Depletion Potential) rating among refrigerants is found in chlorofluorocarbons (CFCs), specifically CFC-11.
CFC-11 has an ODP rating of 1.0, which means it has the highest potential for depleting the ozone layer. However, CFCs have been phased out due to their harmful effects on the ozone layer and are no longer used as refrigerants.