The amplitude of a random signal is uniformly distributed between $-5 \mathrm{~V}$ and $5 \mathrm{~V}$.
If the positive values of the signal are uniformly quantized with a step size of $0.05 \mathrm{~V}$, and the negative values are uniformly quantized with a step size of $0.1 \mathrm{~V}$, the resulting signal to quantization noise ratio is approximately
- $46 \mathrm{~dB}$
- $43.8 \mathrm{~dB}$
- $42 \mathrm{~dB}$
- $40 \mathrm{~dB}$