Signals from fifteen thermocouples are multiplexed and each one is sampled once per second with a 16-bit $ADC$. The digital samples are converted by a parallel to serial converter to generate a serial $PCM$ signal. This $PCM$ signal is frequency modulated with $FSK$ modulator with $1200\; Hz$ as $1$ and $960\; Hz$ as $0$. The minimum band allocation required for faithful reproduction of the signal by the $FSK$ receiver without considering noise is
- $\text{840 Hz to 1320 Hz}$
- $\text{960 Hz to 1200 Hz}$
- $\text{1080 Hz to 1320 Hz}$
- $\text{720 Hz to 1440 Hz}$