Which of the following are the main development phases of disaster recovery (DR) in a...

Huawei outlines theevolution of disaster recovery (DR)in data centers infour phases:

B. Single DC– No DR capability; all services reside in one data center.

C. Primary/Backup DC– Two data centers where one is primary and the other acts as a backup.

A. Two-site three-DC– One production site and two DR sites (or combinations).

D. Multi-site multi-DC– Advanced architecture with distributed data centers and cross-DR capabilities for resilience.

These are officially listed asDR evolution stagesin Huawei's multi-DC solution strategy.