According to HA200 guide
"A user in one database can run a query that references objects in another database, if the
user is associated with a sufficiently privileged user in the remote database. This associated
user is called a remote identity. This is the user who executes the query (or part of the query)
in the remote database, and therefore the user whose authorization is checked.
Cross-database access is not enabled by default and must be configured before such user
mappings can be set up."

So B and C

B and C should be the correct Answer, Refer Hana200 ADM Book