Which option is a characteristic of the online software upgrade on the Cisco ASR 5000 Series?
A. The online upgrade allows active sessions to be maintained until they are self-terminated (subscriber ends the session) or meet the optionally defined upgrade-limit values.
B. The system accepts new sessions during the online upgrade.
C. The final step is to migrate active PSCs to standby PSCs.
D. The online upgrade should not be performed during a planned maintenance window.
