A man in a lift, ascending with an upward acceleration $a$, throws a ball vertically upwards with a velocity $v$, with respect to himself and catches it after $t_1\mathit{ }\mathrm{s}$. Afterwards when the lift is descending with the same acceleration $a$, acting downwards, the man again throws the ball vertically upwards with the same velocity with respect to him and catches it after $t_2 \mathrm{s}$. Which of the following statements is/are correct?

The $x-t$ graph shown in figure represents.

The velocity-time graph of a body moving in a straight line is shown in the figure. The displacement and distance travelled by the body in $6 \mathrm{s}$ are respectively

The acceleration-time graph of a body is shown below.

The most probable velocity-time graph of the body is 

The velocity displacement graph of a particle moving along a straight line is shown in the figure.

Then, the acceleration displacement graph is