The transaction isolation level controls the locking and row versioning behavior of Transact-SQL statements issued by a connection to SQL Server. Which of the following transaction isolation levels is the default in SQL Server 2012?

READ COMMITTED specifies that statements cannot read data that has been modified but not committed by other transactions. This prevents dirty reads. Data can be changed by other transactions between individual statements within the current transaction, resulting in nonrepeatable reads or phantom data. This option is the SQL Server default.