The velocity-time graph of a body is shown in the figure. It implies that at point $B$

Given below are two statements:
Statement $I:$ Area under velocity-time graph gives the displacement of the body in a given time.
Statement $II:$ Area under acceleration-time graph is equal to the change in velocity in the given time.
In the light of given statements,choose the correct answer from the options given below.

Why is instantaneous velocity defined?

$A$ body moves with velocity $v = \ln x \, m/s$ where $x$ is its position. The net force acting on the body is zero at

The displacement of the particle varies with time according to the relation $x = \frac{k}{b}\,[1 - {e^{ - bt}}]$. Then the velocity of the particle is

The figure shows the graph of the $x$-coordinate of a particle moving along the $x$-axis as a function of time. The average velocity during $t=0$ to $6 \,s$ and the instantaneous velocity at $t=3 \,s$ respectively,will be