Explanation:

- The statement “Every legal right has a title, that is to say, certain facts or events by reason of which the right has become vested in its owner” is attributed to a well-known legal philosopher.

- Option 1: Salmond

- John Salmond is noted for his work in jurisprudence and developed the idea of "title" as the basis for the vesting of legal rights.

- Option 2: Austin

- John Austin is famous for his theory of law as commands, not specifically for this view on rights and titles.

- Option 3: Bentham

- Jeremy Bentham is known for utilitarianism and theory of law, but not for this particular statement.

- Option 4: Keeton

- Keeton, a legal theorist, contributed to jurisprudence, but this view is not attributed to him.

Correct Answer: Option 1: Salmond