Which of the following should be implemented to ensure email continuity is not disrupted if one of multiple datacenters experiences an outage?

Geo-clustering, also known as geographic clustering or multi-site clustering, involves configuring servers in different datacenters to work together as a single cluster. This setup allows services like email to failover to a healthy datacenter if another experiences a complete outage, ensuring business continuity.

Offsite backup provides data recovery from a disaster but does not ensure immediate continuity of services like email during an outage; it requires restoration, which causes downtime.

Local load balancing distributes traffic among servers within a single datacenter, improving performance and availability within that specific location, but it does not provide continuity across multiple geographically separate datacenters if one fails entirely.

Multipathing is a technique used to create multiple paths for data transfer between a server and its storage devices, enhancing I/O performance and resilience, but it is not directly related to maintaining email service continuity across different datacenters.