According to the Risk and Information Systems Control documents, implementing record retention tools and techniques is the best solution in this scenario. Record retention involves managing the lifecycle of records, including their creation, usage, storage, and disposal. By implementing record retention policies, organizations can define how long emails and other data should be retained before being deleted. This helps in efficiently managing storage space and reducing unnecessary storage costs.
Establishing e-discovery and data loss prevention (DLP) (Option B) focuses more on legal and compliance aspects and may not directly address the issue of reducing storage costs. Sending notifications when near storage quota (Option C) is a reactive approach and may not prevent the exponential increase in storage costs.
Implementing a bring your own device (BYOD) policy (Option D) is unrelated to the issue of email storage costs.
References = Risk and Information Systems Control Study Manual