What would be the outcome of the above statement?

View the Exhibit and examine the structure of the ORDERS and ORDERJTEMS tables.
In the ORDERS table, ORDERJD is the PRIMARY KEY and ORDER_DATE has the
DEFAULT value as SYSDATE.
Evaluate the following statement:
UPDATE orders
SET order_date=DEFAULT
WHERE order_id IN (SELECT order_id FROM order_items
WHERE qty IS NULL);
What would be the outcome of the above statement?

A.
The UPDATE statement would not work because the main query and the subquery
use different tables.

B.
The UPDATE statement would not work because the DEFAULT value can be used
only in INSERT statements.

C.
The UPDATE statement would change all ORDER_DATE values to SYSDATE
provided the current ORDER_DATE is NOT NULL and QTY is NULL

D.
The UPDATE statement would change all the ORDER_DATE values to SYSDATE
irrespective of what the current ORDER_DATE value is for all orders where QTY is
NULL