Which of the following displacement time (x-t) graphs can possibly represent the one-dimensional motion of a particle?
If we draw a dotted line perpendicular to the time axis as shown below, we see that the line cuts the graph at two points A and B which means that the particle has two different positions x1 and x2 at the same time. This is not possible. Similarly, graphs (b) and (c) are also not possible. But graph (d) is possible.
Hence, the correct choice is (d).