單項選擇題
View the Exhibit and examine the parameters.

User A executes the following command to update the TRANS table: SQL> UPDATE B.trans SET tr_amt=tr_amt+500 WHERE c_code=’C005’;
Before user A issues a COMMIT or ROLLBACK command, user B executes the following command onthe TRANS table:
SQL> ALTER TABLE trans MODIFY (tr_type VARCHAR2(3));
What would happen in this scenario()
A.The ALTER TABLE command modifies the column successfully.
B.The DDL operation gets higher priority and transaction for user a is rolled back.
C.The ALTER TABLE command waits indefinitely until user a ends the transaction.
D.The ALTER TABLE command fails after waiting for 60 seconds due to the resource being busy.