Regarding valid INSERT statements into the ORDERS table:
B . This is a valid statement because it uses TO_DATE for potentially setting a NULL date and provides defaults implicitly where not specified, adhering to the column constraints and requirements.
D . This statement is correctly formatted and provides values for non-optional fields, using DEFAULT implicitly for unspecified optional fields.
Incorrect options:
A: The subquery format and values provided do not match the expected column count and types for direct insert.
C: Incorrect format due to an improper string for the ORDER_MODE and possibly incomplete values.
E: Incorrect syntax; DEFAULT should be correctly capitalized, and the value order and type must match the table structure.