Select all join types that may return unmatched re

Select all join types that may return unmatched records (records from one table that were not matched with any record in another table)?

Cross join
Natural join
Theta join
Left outer join
Full outer join

Explanation

There is no natural join and theta join in SQL.
Cross join will match every record from one table to all records from another table.
Full outer join and left outer join can return records from one table that were not matched with any records from another table.