Answer :
The purpose of the Blackstone Commentaries on the Laws of England is to advocate a common law. Thus, the answer is letter B. The commentary was originally published by Clarendon Press at Oxford. This was divided on the four: rights of persons, rights of things, private wrongs, and public wrongs.
The primary purpose of Blackstone's Commentaries on the Laws of England was "B to advocate for common law," since he was trying to show how effective these laws had been in the past.