Which of the following DNS servers provides fault tolerance, load distribution, and easier remote name resolution for the primary DNS server?

A forwarding server simply forwards unresolved queries to another specified DNS server rather than hosting zone data or providing redundancy.

A root server sits at the top of the DNS hierarchy and resolves queries for top-level domains, not a zone-redundancy or load-distribution role.

A caching-only server stores query responses temporarily but does not hold authoritative zone data and cannot serve as a fault-tolerant backup for the primary.

A slave server is a secondary DNS server that obtains a copy of zone data from the primary (master) server via zone transfers. This arrangement provides fault tolerance because queries can still be resolved if the primary goes offline, distributes the query load, and reduces WAN traffic by handling remote resolution locally.