which server becomes the master NTP server?

Refer to the exhibit.

If the route to 10.1.1.1 is removed from the R2 routing table, which server becomes the master NTP
server?

A.
R2

B.
The NTP server at 10.3.3.3

C.
The NTP server at 10.4.4.4

D.
The NTP server with the lowest stratum number