The correct answer is (c) 54 km/hr.
The speed of the train is the distance it travels divided by the time it takes to travel that distance. In this case, the distance is 480 meters and the time is 32 seconds. So the speed is $480 \text{ m} / 32 \text{ s} = 15 \text{ m/s}$. To convert meters per second to kilometers per hour, we multiply by 3.6 because there are 3.6 kilometers in every 1000 meters and 3600 seconds in every hour. So the speed of the train is $15 \text{ m/s} \times \frac{3.6 \text{ km}}{1000 \text{ m}} \times \frac{3600 \text{ s}}{1 \text{ hr}} = 54 \text{ km/hr}$.
Option (a) is incorrect because 36 km/hr is less than the speed of the train. Option (b) is incorrect because 45 km/hr is less than the speed of the train. Option (d) is incorrect because 63 km/hr is greater than the speed of the train.