Given below are two statements: One is labelled as Assertion $(A)$ and other is labelled as Reason $(R)$.

Assertion $(A)$ : Time period of oscillation of a liquid drop depends on surface tension $(S)$, if density of the liquid is $p$ and radius of the drop is $r$, then $T = k \sqrt{ pr ^{3} / s ^{3 / 2}}$ is dimensionally correct, where $K$ is dimensionless.

Reason $(R)$: Using dimensional analysis we get $R.H.S.$ having different dimension than that of time period.

In the light of above statements, choose the correct answer from the options given below.

• A

  Both $(A)$ and $(R)$ are true and $(R)$ is the correct explanation of $(A)$

• B

  Both $(A)$ and $(R)$ are true but $(R)$ is not the correct explanation of $(A)$

• C

  $(A)$ is true but $(R)$ is false

• D

  $(A)$ is false but $(R)$ is true