What would be the outcome of the above statement?

View the exhibit and examine the data in ORDERS_MASTER and MONTHLY_ORDERS tables.
ORDERS_MASTER
ORDER_ID ORDER_TOTAL
1 1000
2 2000
3 3000
4
MONTHLY_ORDERS
ORDER_ID ORDER_TOTAL
2 2500
3
Evaluate the following MERGE statement:
MERGE_INTO orders_master o
USING monthly_orders m
ON (o.order_id = m.order_id)
WHEN MATCHED THEN
UPDATE SET o.order_total = m.order_total
DELETE WHERE (m.order_total IS NULL)
WHEN NOT MATCHED THEN
INSERT VALUES (m.order_id, m.order_total)
What would be the outcome of the above statement?

A.
The ORDERS_MASTER table would contain the ORDER_IDs 1, 2, 3 and 4.

B.
The ORDERS_MASTER table would contain the ORDER_IDs 1, 2 and 4.

C.
The ORDERS_MASTER table would contain the ORDER_IDs 1, 2 and 3.

D.
The ORDERS_MASTER table would contain the ORDER_IDs 1 and 2.

Explanation:
https://docs.oracle.com/cd/B28359_01/server.111/b28286/statements_9016.htm