Which of the following physical quantities has no dimensions?

In the equation $\frac{dy}{dt} = 2\omega \sin(\omega t + \theta_0)$,what are the dimensions of $(\omega t + \theta_0)$?

The dimension of $\frac{B^{2}}{2 \mu_{0}}$,where $B$ is magnetic field and $\mu_{0}$ is the magnetic permeability of vacuum,is

Two quantities $A$ and $B$ are related by the equation $A/B = m$,where $m$ is linear density and $A$ is force. The dimensions of $B$ are equivalent to which of the following?

Is it possible for a physical quantity to have dimensions but no units?

If $M =$ mass,$L =$ length,$T =$ time,and $I =$ electric current,then the dimensional formula for electrical resistance $R$ is: