A binary channel with capacity 36 kbit/sec is available for PCM voice transmission. If the signal is band-limited to 3.2 kHz, then the appropriate values of quantizing level and the sampling frequency will be, respectively

• A. 32, 3.6 kHz
• B. 64, 7.2 kHz
• C. 64, 3.6 kHz
• D. 32, 7.2 kHz