The orange book was a member of what series of government security standards?

The correct answer is that the orange book is part of the Rainbow Series. This series consists of a collection of documents that were developed by the U.S. Department of Defense (DoD) to provide a standardized framework for assessing the security of computer systems. Each document in the series is associated with a different color code, with the orange book specifically referring to the Trusted Computer System Evaluation Criteria (TCSEC).

The TCSEC established a set of criteria for the evaluation of trusted computer systems, focusing on levels of trust and security features that these systems should possess. The approach facilitated the assessment of systems to ensure they met specific security standards, making it a foundational piece of literature in the field of computer security. The use of color coding in the naming convention not only helps in identifying specific criteria but also signifies the progression and focus of the standards across different areas of security.

In contrast, the other options do not accurately represent the established terms within this context. The Secure Series, Prism Series, and Multi-Color Series are not recognized classifications related to government security standards. The correct identification of the Rainbow Series highlights the significance of structured security assessment criteria that originated to address vulnerabilities and promote secure computing environments.