Which of the following cannot designate a senior protection zone?

Answer: ④ Commissioner of the Metropolitan/Provincial Police Agency

Senior protection zones are designated by local government heads (the 'mayor, etc.'), such as the mayor of a special or metropolitan city or the governor of a special self-governing province. The police commissioner can take traffic measures inside a zone but does not designate it. [Rules on Designation and Management of Protection Zones, Art. 3(1)]