If the differential voltage gain and the common mode voltage gain of a differential amplifier are $48 \mathrm{~dB}$ and $2 \mathrm{~dB}$ respectively, then its common mode rejection ratio is
- $23 \mathrm{~dB}$
- $25 \mathrm{~dB}$
- $46 \mathrm{~dB}$
- $50 \mathrm{~dB}$