Choose the correct relation between polarisation $P$ and electric susceptibility $\chi_{e}$ of a dielectric material. ($E =$ electric field)

If the dielectric constant of a substance is $K = \frac{4}{3}$,then the electric susceptibility $\chi_{e}$ is

The dielectric constant of a metal is ........ .

Which of the following statements is false in the case of polar molecules?

If the dielectric constant and dielectric strength are denoted by $k$ and $x$ respectively,then a material suitable for use as a dielectric in a capacitor must have

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: Net dipole moment of a polar dielectric substance is zero in the absence of an external electric field.
Reason $(R)$: In the absence of an external electric field,the different permanent dipoles of a polar dielectric substance are oriented in random directions.
In the light of the above statements,choose the most appropriate answer from the options given below.