Explanation:

- Option 1: Evidence for audit conclusions

- Working papers contain evidence to support the auditor’s conclusions and judgments. They include details of verification and evaluations made during the audit.

- Option 2: Owned by the client

- This is incorrect. Although the client provides the information, the prepared working papers themselves are not owned by the client.

- Option 3: Owned by the auditor

- Correct. Working papers are the property of the auditor. They are meant for internal use to document the audit process and conclusions drawn.

- Option 4: Retained in auditor’s office until a change in auditors

- Working papers are usually retained for a certain number of years as per auditing standards, but not just until a change in auditors.