Answer
See the graph below.
Work Step by Step
The wave took about 4 seconds to be fully represented at $x=2$ m, while it is moving at 1 m/s to the left.
This means that the width of the wave is 4 m.
The history graph of the point at $t=0$ s, the leading edge is at $x=2$ m, and $D=0$ cm.And since the wave is 4 m wide, the trailing edge is then at $x=6$ m.
At $t=2$ which is after 2 s, the point rises up to $D=1$ mm while the wave is moving to the left.
After 2 extra seconds, the point remains at the same height during these two seconds and suddenly drops to zero at the end of them.
See the graph below.
