Which of the following commands sets the local router to serve as an authoritative time source?

A.
ntp server

B.
ntp master

C.
ntp authenticate

D.
ntp peer

Explanation:
The ntp master command sets the local router to serve as an authoritative time source.
The ntp server command is used to specify an external time source that the local router should use as its time
source.
The ntp authenticate command is used to enable the authentication of time source to which the local router has
been configured to use. It is the first step in a process that must also include the specification of a hashing
algorithm and a key, both of which must match on the time source.
The ntp peer command is used to configure the local router to synchronize a peer or to be synchronized by a
peer. It does not make the local router authoritative as a time source like the ntp master command.
Objective:
Infrastructure Services
Sub-Objective:
Configure and verify NTP operating in a client/server mode

Cisco > Support > Cisco IOS Basic System Management Command Reference > ntp master