zone1 is a non-global zone that has been configured and installed.
zone1 was taken down for maintenance, and the following command was run:
zoneadm -z zone1 mark incomplete
The following information is displayed when listing the zones on your system: 
Which task needs to be performed before you can boot zone1?
A.
The zone needs to be installed.
B.
The zone needs to be brought to the ready state.
C.
The zone needs to be uninstalled and reinstalled.
D.
The zone needs to be brought to the complete state.
Explanation:
If administrative changes on the system have rendered a zone unusable or
inconsistent, it is possible to change the state of an installed zone to incomplete.
Marking a zone incomplete is irreversible. The only action that can be taken on a zone marked
incomplete is to uninstall the zone and return it to the configured state.
Reference: Installing, Booting, Halting, Uninstalling, and Cloning Non-Global Zones (Tasks), How
to Mark an Installed Non-Global Zone Incomplete
C
C is the correct. man zoneadm
incomplete
Change the state of an installed zone to incomplete.
This command can be useful in cases where adminis-
trative changes on the system have rendered a zone
permanently unusable or inconsistent. This change
cannot be undone, except by uninstalling the zone.
I sat this exam this month (Apr 2016), and these questions are still very much relevant. Thanks for all the input from users.
Hi! All!
Passed Oracle Solaris 11 Administration 1Z0-821 exam with a good score of 90% (the passing line is 64% now)!
Got 70 questions in total, and questions were on:
1. Installing Oracle Solaris 11 using an Interactive Installer
2. Administering Services
3. Setting Up and Administering Data Storage
4. Administering Oracle Solaris Zones
5. Setting Up and Administering User Accounts
6. Controlling Access to Systems and Files
(New) 7. Managing the SYSLOG facilityManaging the CRON facility
(New) 8. Managing the SYSLOG facility
Pay close attention to the up 7 & 8 topics when preparing for the 1Z0-821 exam. Questions on those two topics are not available on this site.
And, you can refer to the most valid 1Z0-821 dumps (2017 version) here:
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(Those questions are part of PassLeader 1Z0-821 dumps, recommend to get its full version 1Z0-821 dumps with VCE and PDF.)
Good Luck!
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Best Regards!!!