A user has reported an issue with wireless VoIP phones dropping calls during business hours. When working late or in the evenings, the user does not experience call drops. When the network technician investigates the issue, all WAPs have balanced the number of connections evenly and are not dropping off the network. The network technician connects to the wireless network in the user`s office and starts a continuous ping to an external server. The results show a drastic and varied response time for each packet. Which of the following is the MOST likely cause of the dropped calls? 

Answer options:

A. No QoS configured on the network
B. Signal-to-noise ratio
C. Interference from the microwave in the breakroom
D. Rogue AP installed in the office

B