Question: Which of the following statements about SQL transactions and isolation levels is correct?

A) Transactions in SQL are always executed in serializable mode to ensure maximum isolation and prevent dirty reads.
B) The READ UNCOMMITTED isolation level allows transactions to read data that has been modified by other transactions but not yet committed.
C) Transactions set to READ COMMITTED can read uncommitted data from other transactions, which helps in optimizing performance.
D) The REPEATABLE READ isolation level guarantees that if a transaction reads a row, it can read the same row again and get the same data, even if other transactions are modifying that row concurrently.