Which type of software is most likely to be reviewed by the most personnel, with the most varied perspectives?

Database management software can be open source or proprietary; its review audience is typically limited to specific developers or users, not the broad public.

Open source software has its source code publicly available, allowing a large, global community of developers, security researchers, and users to review, audit, and contribute to it, leading to the most varied perspectives and widespread scrutiny.

'Secure software' is a quality or goal for any software, not a distinct category of software development methodology that dictates review audience size.

Proprietary software has its source code kept confidential, limiting review to internal development teams and authorized auditors, restricting the number and variety of reviewers.