Explanation:

Sure, here's a brief explanation for each option:

- Option 1: Salmond

- John Salmond is known for his writings on law, especially legal rights and duties.

- However, Salmond did not explicitly advocate that rights are only the "right to do duty."

- Option 2: Duguit

- Léon Duguit, a French jurist, strongly argued that individuals do not have subjective rights; instead, what they have is the duty to always perform their functions or duties.

- Duguit believed that the only "right" anyone has is the right to do their duty.

- Option 3: Bentham

- Jeremy Bentham, an English philosopher, was critical of natural rights and emphasized utilitarianism.

- He did not equate rights exclusively with duty in the same way as Duguit.

- Option 4: None of the above

- This is incorrect, since Duguit does fit the statement.

Correct Answer: Option 2 – Duguit