What is the probable cause of this error?

View the Exhibit.

You have placed the following code in a Post insert trigger on the Orders block:
SELECT orders_seq.NEXTVAL
INTO :orders.order_id
FORM SYS.dual;
You have also set Item properties for the Order_Id Item in the form so that users cannot directly
enter an Order ID.
As the SUMMIT user, you run the form to test it. Yon are able to insert a record in the block, but
when you click Save, you have a database error as shown in the Exhibit.
What is the probable cause of this error?

A.
The code should beinPre_insert triggerinstead

B.
The code should beina database triggerinstead

C.
You should change the code to select the sequence number from SUMMIT.dualinstead.

D.
You should create the sequenceinthe database, because the runtime error is anindication that
is does not exist.

E.
You should assign a temporary value to the Order_Id item before saving the form.