A particle covers a distance from A to B over a period of time; the...

The distance versus time plot for movement of a particle from $A$ and $B$ is shown in the diagram.
From graph, it is a slope of distance-time graph for position $A$ to $C$ and $D$ to $B$ is always positive, therefore both the average speed and instantaneous speed are not always zero, therefore, option (1) is not correct. $\text{ Average velocity }=\frac{\text{ Total displacement from A to B }}{\text{ Total time interval }}$Since, total displacement depends on straight distance between initial and final points, hence, displacement between $A$ to $B$ always non zero, therefore the average speed is always non zero. Since, no distance is travelled between point $C$ to $D$ is zero. Hence, instantaneous speed at every instant between $C$ to $D$ is zero. Hence, option (2) is correct and option (3) and (4) are incorrect.