Which MERGE statement is valid?

Examine the structure of the EMPLOYEES and NEW_EMPLOYEES tables: Which MERGE
statement is valid?

A.
MERGE INTO new_employees cUSING employees e ON (c.employee_id =
e.employee_id) WHEN EXISTS THEN UPDATE SET

B.
MERGE INTO new_employees c USING employees e ON (c.employee_id =
e.employee_id) WHEN MATCHED THEN UPDATE SET

C.
name = e.first_name ||’,’|| e.last_name WHEN NOT MATCHED THEN INSERT value
S(e.employee_id, e.first_name ||’, ‘||e.last_name);

D.
MERGE new_employees c FROM employees e ON (c.employee_id = e.employee_id)
WHEN MATCHED THEN UPDATE SET H. name = e.first_name ||’,’|| e.last_name WHEN
NOT MATCHED THEN INSERT INTO new_employees valueS(e.employee_id, e.first_name
||’, ‘||e.last_name);

E.
name = e.first_name ||’,’|| e.last_name WHEN NOT MATCHED THEN INSERT value
S(e.employee_id, e.first_name ||’, ‘||e.last_name);

F.
name = e.first_name ||’,’|| e.last_name WHEN NOT MATCHED THEN INSERT
valueS(e.employee_id, e.first_name ||’, ‘||e.last_name);

G.
MERGE new_employees c USING employees e ON (c.employee_id = e.employee_id)
WHEN EXISTS THEN UPDATE SET