Correct Answer: Truck : Road

Solution : Given:
Train : Track :: ? : ?

First option: Car : Four Wheeler; A car is a means of transport but "four-wheeler" is not a path on which it runs.
Second option: Aeroplane : Fly; An aeroplane is a means of transport but "fly" is not a path on which it runs.
Third option: Truck : Road; A truck is a means of transport and a road is the path on which it runs.
Fourth option: Car : Speed; A car is the means of transport but "speed" is not a path on which it runs.

Hence, the third option is correct.