When you configure Microsoft Purview DLP policies for the Teams chat and channel messages location, the following entities are protected:
1:1 and n:n chats (private chats between two or more users).
Team channel messages (including the General channel and all standard channels).
Private channel messages.
This means that if a DLP policy is applied to User1 and User2, it will monitor and enforce rules across:
Chats between User1 and User2 (1:1 or group chats).
Any channel conversations they participate in (General or other channels).
Private channels they belong to.
Incorrect options:
A (1:1/n chats and general channels only) # Excludes private channels, but DLP supports them.
B (1:1/n chats and private channels only) # Excludes general channels, but DLP supports them too.
Reference:
Microsoft Learn: Learn about data loss prevention in Microsoft Teams
Quote: "When DLP policies are applied to Teams chat and channel messages, they protect messages in 1:1 chats, group chats, channel messages (including private channels)."