From which law and principle can the electric field of an electric dipole be obtained?

$A$ neutral water molecule $(H_2O)$ in its vapor state has an electric dipole moment of magnitude $6.4 \times 10^{-30} \ C \cdot m$. How far apart are the molecule's centers of positive and negative charge?

$A$ 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?

Two opposite and equal charges of $4 \times 10^{-8} \ C$ are placed at a distance of $2 \times 10^{-2} \ cm$ to form a dipole. If the dipole is placed in an external electric field of $4 \times 10^8 \ N/C$,calculate the maximum torque and the work done to rotate it by $180^{\circ}$.

An electric dipole with dipole moment $P$ and moment of inertia $I$ is placed in a uniform electric field of intensity $E$. If the dipole is slightly rotated,the angular frequency of its oscillation is ........

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: