To understand the meaning of the transaction isolation level TRANSACTION_REPEATABLE_READ, we need to know about transaction isolation levels in database management systems.

Transaction isolation level is a concept that ensures the correctness and consistency of database transactions. It defines the level of isolation between concurrent transactions in the system.

The TRANSACTION_REPEATABLE_READ isolation level guarantees that during the transaction, any row that is read will be locked for the duration of the transaction. This means that if the transaction tries to read the same row again, it will get the same value as before. This ensures that the transaction sees a consistent snapshot of the data.

Now let's go through each option to see which one is correct:

A. (a) Dirty reads, non-repeatable reads, and phantom reads can occur - This option is incorrect. The TRANSACTION_REPEATABLE_READ level prevents dirty reads and non-repeatable reads, but phantom reads can still occur.

B. (b) Dirty reads are prevented; non-repeatable reads and phantom reads can occur - This option is incorrect. The TRANSACTION_REPEATABLE_READ level prevents dirty reads, but non-repeatable reads and phantom reads can still occur.

C. (c) Dirty reads and non-repeatable reads are prevented; phantom reads can occur - This option is correct. The TRANSACTION_REPEATABLE_READ level prevents dirty reads and non-repeatable reads, but phantom reads can still occur.

D. (d) Dirty reads, non-repeatable reads, and phantom reads are prevented - This option is incorrect. The TRANSACTION_REPEATABLE_READ level only prevents dirty reads and non-repeatable reads, but phantom reads can still occur.

Therefore, the answer is: C. (c) Dirty reads and non-repeatable reads are prevented; phantom reads can occur.