The various levels of locking include Page Level Locking, Table Level Locking, and Row Level Locking. Among these, Row Level Locking provides the highest degree of concurrency. Let's see why.
1. Page Level Locking:
Page Level Locking is the coarsest level of locking. In this method, a page is locked instead of a row or a table. When a transaction accesses a page, it acquires a lock on the entire page. This means that other transactions cannot access any of the rows on that page until the lock is released. This method is not suitable for high concurrency databases because it can lead to contention and reduce performance.

2. Table Level Locking:
Table Level Locking is a more fine-grained locking method than Page Level Locking. In this method, the entire table is locked instead of a page or a row. When a transaction accesses a table, it acquires a lock on the entire table. This means that other transactions cannot access any of the rows on that table until the lock is released. This method is also not suitable for high concurrency databases because it can lead to contention and reduce performance.

3. Row Level Locking:
Row Level Locking is the finest level of locking. In this method, each row is locked independently of other rows. When a transaction accesses a row, it acquires a lock on that row only. This means that other transactions can access other rows on the same table at the same time. This method provides the highest degree of concurrency because it minimizes the contention for resources.

Conclusion
In summary, Row Level Locking provides the highest degree of concurrency among the different levels of locking in a relational database. It allows multiple transactions to access different rows on the same table simultaneously, thereby reducing contention and improving performance.