In advanced features, which setting must be turned on to obstruct files even if a 3rd party AV is used?

Answer options:

A.Turn on EDR with block mode
B.Automated Investigation
C.Allow or block file
D.All of the above

Correct Answer: A
Option A is correct. EDR with block mode can be used with third party AV.
Option B is incorrect. “Allow or block file” feature requires Defender AV.
Option C is incorrect. Automated investigations do not block files.
Reference: 

https://docs.microsoft.com/en-us/microsoft-365/security/defender-endpoint/microsoft-defender-antivirus-compatibility?view=o365-worldwide