Which factor will most influence how controls should be layered?

Layering controls effectively is essential in managing risks within an organization's information systems. The correct choice focuses on the extent to which controls are subject to the same threat. This factor is crucial because controls ought to be designed in a way that addresses multiple aspects of a threat landscape. When controls face the same threat, it increases the likelihood that a weakness in one control could be exploited, potentially leading to a failure in security.

Layering controls that are designed to combat the same threat allows for a more robust defense. For instance, if two or more controls are put in place to mitigate risks from the same type of attack (such as malware), they can provide alternative forms of defense, ensuring that if one control fails, others can still offer protection. This redundancy is what makes layered security effective, as it reduces the probability of a successful security breach.

In contrast, while procedural controls, total cost of ownership, and control failures in a closed condition are relevant considerations in overall security management, they do not directly address the necessity of control layering in response to common threats. Thus, the emphasis on how controls relate to shared threats is the most influential factor in determining the appropriate layering strategy.