A student is provided with a variable voltage source $\mathrm{V}$, a test resistor $R_{T}=10 ~\Omega$, two identical galvanometers $G_{1}$ and $G_{2}$ and two additional resistors, $R_{1}=10 ~M \Omega$ and $R_{2}=0.001 ~\Omega$. For conducting an experiment to verify ohm's law, the most suitable circuit is: