A vulnerability assessment requires compliance with the cloud service provider's terms of service.
Managing Cloud documentation explains that vulnerability scanning and testing can affect cloud infrastructure and other tenants if not properly authorized.
CSPs define acceptable testing activities to protect shared environments. Customers must follow these guidelines to avoid violating contracts or causing service disruptions. Many CSPs require prior notification or explicit permission before conducting vulnerability assessments.
The other methods involve internal development processes and do not impact cloud infrastructure directly.
Therefore, vulnerability assessment is the correct answer.