Two analogies that relate places/locations to the associated travel mode is given in the form "A : B. C : ?". "A : B" relates place A to travel mode B. Your task is to replace the question mark (?) with the appropriate travel mode for the given place C, following the "A : B" relation.
--------
Question: airport : car. hospital : ?

Answer: ambulance


Question: store : car. school : ?

Answer: bus


Question: spain : airplane. mall : ?

Answer:
bus