※This sample exam is different from those that appear in the actual OSS-DB Exam.
PostgreSQL employs a license based on BSD called the ‘PostgreSQL license’. There are many kinds of licenses based on BSD, but a common feature, unlike GPL's copy left clause, for the use of secondary works (for example, programs created by modifying source code) there is no need. For example, you may sell secondary works for a fee and not publish their source code.
Therefore, the correct answer are B and E.