To solve this question, the user needs to have knowledge of Oracle PL/SQL exceptions and their syntax.
The correct answer is option C. TWO_MANY_ROWS ORA-01422 is not a valid Oracle PL/SQL exception.
Explanation for each option:
A. NO_DATA_FOUND ORA-01403: This is a valid exception in Oracle PL/SQL. It is raised when a SELECT INTO statement returns no rows.
B. DUP_VAL_ON_INDEX ORA-00001: This is a valid exception in Oracle PL/SQL. It is raised when a unique index constraint is violated.
C. TWO_MANY_ROWS ORA-01422: This is not a valid exception in Oracle PL/SQL. It is an invalid exception.
D. OTHERS: This is a valid exception in Oracle PL/SQL. It is used to catch any exception that is not explicitly handled.
E. None of the above. These are all valid: This option is incorrect as option C is not a valid exception.
Therefore, the answer is: C.