Which of the following table locks will prevent concurrent applications (except for the lock owner) from having any access to the table, except read access by applications using UR isolation level?

X locks (exclusive locks) provide the most restrictive locking mode in DB2. An X lock allows only the lock owner to access the table - all other applications are blocked from any access. The UR (Uncommitted Read) isolation level allows dirty reads, but even UR applications cannot read a table locked exclusively by another transaction. The question specifically identifies X lock as preventing concurrent access while making a narrow exception for UR-level readers.