Explanation:

- Option 1: The will theory

- Focuses on the idea that rights are manifestations of a person's will.

- Emphasizes autonomy and control over one's own actions.

- Option 2: The interest theory

- Suggests that rights protect individual interests and well-being.

- Highlights the function of rights in promoting human welfare.

- Option 3: Both (a) and (b)

- Recognizes both theories as fundamental in understanding legal rights.

- Combines elements of autonomy and interest protection.

- Option 4: None of these

- Disregards both dominant theories as explanations for legal rights.

Answer: Option 3: Both (a) and (b)