What is most likely to cause of the issue?

A group of users try to access one of universal containers connected apps and receive the following error message: "Failed: Not approved for access".

What is most likely to cause of the issue?
A . The use of high assurance sections are required for the connected App.
B . The users do not have the correct permission set assigned to them.
C . The connected App setting "All users may self-authorize" is enabled.
D . The salesforce administrators gave revoked the Oauth authorization.

Answer: B