Where is parking prohibited?
Answer: D — All of the above.
Prohibiting parking in all the options listed ensures the safety and accessibility of the roadway. Option A, double parking, prevents vehicles from maneuvering around parked cars and can cause traffic congestion. Option B, parking on highway pavement not marked for parking, can also impede the flow of traffic and potentially cause accidents. Option C, parking within 15 feet of a fire hydrant, is crucial for emergency responders to have access to hydrants in case of a fire. Therefore, all of the options listed are important in maintaining safe and efficient use of the roadways and are prohibited for parking.