Mark the correct statements for a particle going on a straight line ($x$-position coordinate, $v$-velocity and $a$-acceleration):

A particle moves along the $Y$ -axis and its $y$ -coordinate $\left(y\right)$changes with time $\left(t\right)$ as $y=u(t-2)+a(t-2{)}^2$.

The graph below gives the coordinator of a particle travelling along the $X-$axis as a function of $\tan \theta$. $AM$ is the tangent to the curve at the starting moment and $BN$ is tangent at the end moment $\left({\theta }_1={\theta }_2=120°\right)$

The direction $(i$ or $-i)$ of acceleration during the first $10$ seconds is

Three elephants $A$, $B$ and $C$ are moving along a straight line with constant speed in the same direction, as shown in the figure. Speed of $A$ is $5 \mathrm{m} {\mathrm{s}}^{-1}$ and speed of $C$ is $10 \mathrm{m} {\mathrm{s}}^{-1}$. Initially, the separation between $A$ and $B$ is $d$ and between $B$ and $C$ is also $d$. When $B$ catches $C$ separation between $A$ and $C$ becomes $3d$. Find the speed of $B \left(\mathrm{in} \mathrm{m} {\mathrm{s}}^{-1}\right)$