instruction:
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:
moon : rocket. mainland : ?
answer:
boat


question:
airport : taxi. portland : ?
answer:
car


question:
australia : airplane. moon : ?
answer:

rocket