Explanation:

- Disgraceful conduct generally implies actions or behavior that bring about shame or dishonor.

- Option 1: Shameful behaviour

- This is the correct interpretation of disgraceful conduct.

- It suggests actions that are embarrassing, humiliating, or dishonorable.

- Such behavior attracts disapproval from society or peers.

- Correct Answer

- Option 2: Reputable behaviour

- This means behavior that is regarded positively and with respect.

- It is the opposite of disgraceful conduct.

- Option 3: Unauthenticated behaviour

- This pertains to behavior that lacks verification or proof.

- It does not specifically relate to disgraceful conduct.

- Option 4: None of them

- This option is incorrect since option 1 matches disgraceful conduct.