Which one of the following is dimensionless physical quantity?

If $C$ and $L$ denote capacitance and inductance respectively, then the dimensions of $LC$ are

The force $F$ on a sphere of radius $'a'$ moving in a medium with velocity $'v'$ is given by $F = 6\pi \eta av$. The dimensions of $\eta $ are

What is the dimensions of impedance?

Dimensions of kinetic energy are

Of the following quantities, which one has dimensions different from the remaining three