Explanation/Reference:
D: The rolling upgrade process includes stopping the Administration Server, installing the upgrade, restarting the Administration Server, and then doing the same for each Managed Server in the cluster.
E: You should not make configuration changes during the upgrade process until all the servers in the cluster have been upgraded. This is especially true for new configuration options.
Note: Rolling Upgrade is the process of upgrading a running WebLogic Server cluster with a patch, maintenance pack, or minor release without shutting down the entire cluster or domain. During the rolling upgrade of a cluster, each server in the cluster is individually upgraded and restarted while the other servers in the cluster continue to host your application.
Incorrect Answers:
A: You should not make configuration changes during the upgrade process until all the servers in the cluster have been upgraded.
B: Rolling upgrade applies only to upgrades within a major product version. For example, you can upgrade from 10.0 to 10.3.3, but cannot upgrade from 9.0 to 10.0.
C: The rolling upgrade process includes stopping the Administration Server, installing the upgrade, restarting the Administration Server, and then doing the same for each Managed Server in the cluster.
Reference: http://docs.oracle.com/cd/E14571_01/web.1111/e13754/rolling_upgrade.htm#WLUPG272