The described data, rarely accessed, fixed, and requiring multi-year preservation for compliance, is the textbook definition of archival content, and the correct storage strategy for this profile is data archiving onto low-cost, high-capacity storage media specifically designed for long-term retention rather than frequent access, minimizing ongoing storage cost per unit of retained data over the required retention period. Archiving solutions are purpose-built for exactly this cost-versus-retention-duration tradeoff, since they forgo the performance characteristics needed for active data in exchange for substantially lower cost at scale. Frequent data backups to the cloud (A) are designed around a rotation and retention schedule oriented toward operational recovery of recently changed data, not multi-year compliance preservation, and running frequent backup cycles for static, unchanging historical records wastes cost and effort without improving protection. Replication to a hot standby site (B) is intended to support near-continuous application availability and rapid failover for active production systems, an expensive, performance-oriented solution entirely disproportionate to the needs of rarely-accessed historical records. A fault-tolerant server cluster (D) addresses compute and application availability, not long-term, cost-efficient data storage, and has no direct relationship to retaining historical records economically. Archiving to low-cost storage is correct.

Reference topic: Replication and Data Archiving - Cost-Effective Long-Term Compliance Archiving.