Here X-axis represents time and Y-axis represents distance.
(a) In the first graph, we observe that when the time changes, distance also varies at the same rate.
When we move along time axis away from the origin, then the graph is strictly increasing.
Hence, the object is moving at a uniform speed.
(b) In the graph (b), we observe that initially graph increases steadily i.e. at a uniform speed and after a certain period of time, it comes to rest position i.e. constant.
(c) In the graph (c), we see that the graph increases strictly with non-uniform speed and then slowly comes to the rest position.