The current in resistance $R _2$ would be zero if
$(A)$ $V_1=V_2$ and $R_1=R_2=R_3$
$(B)$ $V_1=V_2$ and $R_1=2 R_2=R_3$
$(C)$ $V_1=2 V_2$ and $2 R_1=2 R_2=R_3$
$(D)$ $2 V _1= V _2$ and $2 R _1= R _2= R _3$
$(A)$ the current $I$ through the battery is $7.5 \mathrm{~mA}$
$(B)$ the potential difference across $R_{\mathrm{L}}$, is $18 \mathrm{~V}$
$(C)$ ratio of powers dissipated in $R_1$ and $R_2$ is $3$
$(D)$ if $R_1$ and $R_2$ are interchanged, magnitude of the power dissipated in $R_{\mathrm{L}}$ will decrease by a factor of $9$


