HOTSPOT
Your network contains an Active Directory domain named contoso.com. All DNS servers host a DNS zone named adatum.com. The adatum.com zone is not Active Directory-integrated. An administrator modifies the start of authority (SOA) record for the adatum.com zone. After the modification, you discover that when you add or modify DNS records in the adatum.com zone, the changes are not transferred to the DNS servers that host secondary copies of the adatum.com zone.
You need to ensure that the records are transferred to all the copies of the adatum.com zone.
What should you modify in the SOA record for the adatum.com zone? To answer, select the appropriate setting in the answer area.
Answer: 
Explanation:
When a DNS server receives an update through Active Directory replication:
If the serial number of the replicated record is higher than the serial number in the SOA record of the local copy of the zone, the local zone serial number is set to the serial number in the replicated record.
Note Each DNS record in the zone has a copy of the zone serial number at the time when the record was last modified.
If the serial number of the replicated record is the same or lower than the local serial number, and if the local DNS server is configured not to allow zone transfer of the zone, the local zone serial number is not changed.
If the serial number of the replicated record is the same or lower than the local zone serial number, if the DNS server is configured to allow a zone transfer of the zone, and if the local zone serial number has not been changed since the last zone transfer occurred to a remote DNS server, then the local zone serial number will be incremented. Otherwise that is if a copy of the zone with the current local zone serial number has not been transferred to a remote DNS server, the local zone serial number is not changed.