A body is projected vertically upward from ground. If we neglect the effect of air, then which one of the following is the best representation of variation of speed $\left(v\right)$ with time $\left(t\right)$

The displacement-time graph for two particles $A$ and $B$ is as follows. The ratio $\frac{v_A}{v_B}$ is

Figure shows the position of a particle moving on the $x$-axis as a function of time

The position $\left(x\right)$ of a particle moving along $x$-axis varies with time $\left(t\right)$ as shown in figure. The average acceleration of particle in time interval $t=0$ to $t=8 \mathrm{s}$ is

The position $\left(x\right)$-time $\left(t\right)$ graph for a particle moving along a straight line is shown in figure. The average speed of particle in time interval $t=0$ to $t=8 \mathrm{s}$ is