What is the behavior of the Isilon time and date settings and what is the best practice?

What is the behavior of the Isilon time and date settings and what is the best practice?
A . SMB time sync takes precedence over the NTP service SMB time is enabled by default on the cluster Best Practice: do not use SMB time, use NTP for cluster and Domain Controller
B . NTP service takes precedence over SMB time sync SMB time is enabled by default on the cluster Best Practice: do not use NTP time, use SMB for cluster and Domain Controller
C . NTP service takes precedence over SMB time sync SMB time is enabled by default on the cluster Best Practice: do not use SMB time, use NTP for cluster and Domain Controller
D . SMB time sync takes precedence over the NTP service SMB time is not enabled by default on the cluster Best Practice: do not use NTP time, use SMB for cluster and Domain Controller

Answer: C