Analyzing the given SQL statements on the ORDER_ITEMS table:

D. Statement 2 may return multiple rows of output: Statement 2 groups the results by ORDER_ID, which means it calculates the maximum UNIT_PRICE * QUANTITY for each ORDER_ID, potentially returning multiple rows depending on the number of unique ORDER_IDs in the table.

E. Statement 1 returns only one row of output: Statement 1 computes the maximum product of UNIT_PRICE and QUANTITY across all entries in the ORDER_ITEMS table, returning a single row with the maximum value.

Incorrect options:

A: Since Statement 2 groups by ORDER_ID, it does not necessarily return just one row; it returns one row per ORDER_ID.

B: These statements do not yield the same output; Statement 1 returns a single maximum value, while Statement 2 returns the maximum value per ORDER_ID.

C: If either UNIT_PRICE or QUANTITY is NULL, the product for that row will be NULL, but the MAX function ignores NULL values in its calculation unless all rows are NULL, in which case it returns NULL.