Which of the following is the BEST way to ensure that application hardening is included...

The best way to ensure that application hardening is included throughout the software development life cycle (SDLC) is to include qualified application security personnel as part of the process. Application hardening is the process of applying security measures and techniques to an application to reduce its attack surface, vulnerabilities, and risks. Application hardening should be integrated into every stage of the SDLC, from planning and design to development and testing to deployment and maintenance. Including qualified application security personnel as part of the process helps to ensure that application hardening is performed effectively and consistently, as well as to provide guidance, feedback, and support to the developers, testers, and project managers. The other options are not as effective or sufficient as including qualified application security personnel as part of the process, as they do not address the root cause of the lack of application hardening, which is the gap in skills and knowledge among the SDLC participants.

References: CDPSE Review Manual, 2021, p. 131