NTP is a network protocol used to synchronize computer clocks with an NTP server. Which of the following statements about NTP is false?
A. NTP is a network layer protocol in the TCP/IP protocol suite.
B. NTP packets are transmitted through UDP.
C. The master time server directly synchronizes with the standard reference clock through cables or radio signals.
D. The stratum indicates the hierarchy for clock synchronization. The value 1 indicates the highest clock precision.