Which statement describes a disadvantage of using the Cisco TFTP service to serve IP phone load files?
A. The Cisco TFTP services can run on only one Cisco Unified Communications Manager server in a cluster.
B. Because TFTP operates on top of UDP, there is a high risk of corrupted load file delivery at the completion of the TFTP process due to undetected data loss in the network.
C. If a response is not received in the timeout period, the TFTP server will not resend the data packet.
D. Packet loss can significantly increase the TFTP session completion time.
E. Because TFTP operates with an adaptive timeout period, the time to complete the file transfer is unpredictable.
Bad explanation
Real explanation –
https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/srnd/collab11/collab11/netstruc.html
If a response is not received in the timeout period (4 seconds by default), the sender will resend the data packet or acknowledgment. When a packet has been sent five times without a response, the TFTP session fails. Because the timeout period is always the same and not adaptive like a TCP timeout, packet loss can significantly increase the amount of time a transfer session takes to complete.