正解:C
The recommended minimum Signal-to-Noise Ratio (SNR) for Voice applications in networks is 25 dB. This level of SNR ensures that voice traffic has sufficient quality and clarity, reducing the likelihood of data corruption and retransmissions. References := Cisco Meraki Documentation: Signal-to-Noise Ratio (SNR) and Wireless Signal Strength4
https://documentation.meraki.com/MR/WiFi_Basics_and_Best_Practices/Signal-to-Noise_Ratio_(SNR)_and_W