Attempting to start the observer raises an error: DGMGRL> start observer: DGM-16954: Unable to open and lock the Observer configuration file Failed. Identify two possible ways to start the observer successfully. 

Answer options:

A. Set the Observer Override property to TRUE before starting the observer.
B. Create a broker configuration and enable Fast-Start Failover before starting the observer.
C. Start the observer using a different observer configuration file.
D. Start the observer in a different working directory.
E. Enable Fast-Start Failover before starting the observer.

CD

Error code: DGM-16954 - Description: Unable to open and lock the Observer configuration file Cause: The Observer configuration file cannot be opened or cannot be locked for exclusive access. Action: Make sure the Observer has the correct operating system privileges to write the file and there is no other Observer that is using the same file. Try the command again. References: https://www.oraexcel.com/oracle-12cR1-DGM-16954