What is the average speed between X and Y?

From point zero to point x the graph shows in a curve pattern which means the rate of change of speed is not uniform, and from point x to point y the graph shows straight line which means the rate of change of its speed is uniform. At this condition we could determine the average speed. We could determine the average speed using this equation.

Thus we determine average speed by

The answer must be letter B 0.30 m/s