JEE Main 2008 — Motion In One Dimension Question with Solution

A body is at rest at $x=0$. At $t=0$, it starts moving in the positive $x$-direction with a constant acceleration. At the same instant another body passes through $x=0$ moving in the positive $x$ direction with a constant speed. The position of the first body is given by ${\mathrm{x}}_1(\mathrm{t})$ after time ' $\mathrm{t}$ ' and that of the second body by $x_2(t)$ after the same time interval. Which of the following graphs correctly describes $\left(x_1-x_2\right)$ as a function of time ' $t$ '?