Units & Dimensions question from NEET 1996 (AIPMT)

Answer: (a)

1. $L/R$ is the time constant of an LR circuit, so it has the dimension of time.
2. $LC$ has dimension $\mathrm{T^2}$ (since $\omega = 1/\sqrt{LC}$), $R/L$ is $\mathrm{T^{-1}}$, $C/L$ is not time.
3. So the answer is (a) $L/R$.