A parallel plate capacitor with circular plates of radius $R$ is being charged. The displacement current between the plates is equal to the conduction current in the wires. If the rate of change of electric field is $\frac{dE}{dt}$, what is the magnetic field $B$ at a distance $r<R$ from the axis?

1. A.$\frac{{\mu }_0{ϵ}_{0}r}{2}\frac{dE}{dt}$
2. B.$\frac{{\mu }_0{ϵ}_0{R}^2}{2r}\frac{dE}{dt}$
3. C.${\mu }_0{ϵ}_{0}r\frac{dE}{dt}$
4. D.$\frac{{\mu }_0{ϵ}_{0}R}{2}\frac{dE}{dt}$