$A$ neutral ammonia $(NH_3)$ molecule in its vapour state has an electric dipole moment of magnitude $5 \times 10^{-30} \ C \cdot m$. How far apart are the molecule's centres of positive and negative charge?

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: The potential $(V)$ at any axial point, at $2 \ m$ distance $(r)$ from the centre of the dipole of dipole moment vector $\vec{P}$ of magnitude $4 \times 10^{-6} \ C \ m$, is $\pm 9 \times 10^3 \ V$.
(Take $\frac{1}{4 \pi \epsilon_0} = 9 \times 10^9 \ SI$ units)
Reason $R$: $V = \pm \frac{1}{4 \pi \epsilon_0} \frac{P}{r^2}$, where $r$ is the distance of any axial point, situated at $2 \ m$ from the centre of the dipole.
In the light of the above statements, choose the correct answer from the options given below:

Three point charges $+q$,$-2q$ and $+q$ are placed at points $(x = 0, y = a, z = 0)$,$(x = 0, y = 0, z = 0)$ and $(x = a, y = 0, z = 0)$ respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly are

Mention the direction of the electric dipole moment. Write the $SI$ unit of the electric dipole moment.

An electric dipole of length $4 \ cm$ is placed with its axis making an angle of $30^{\circ}$ with a uniform electric field of $10^6 \ N/C$. If it experiences a torque of $20 \sqrt{3} \ Nm$,then the potential energy of the dipole is $:-$ (in $J$)

An electric dipole consists of two particles, each of mass $1 \ kg$, separated by $1 \ m$, carrying charges $1 \ \mu C$ and $-1 \ \mu C$ respectively. It is in equilibrium in a uniform electric field of $2 \times 10^4 \ Vm^{-1}$. If it is deflected by a small angle $2^{\circ}$, the minimum time taken by it to come back again to the mean position is (in seconds): (in $\pi$)