Which of the following provides data the best fault tolerance at the LOWEST cost?

Load balancing distributes network or application traffic for availability and performance, but does not provide data redundancy or fault tolerance against disk failure.

Clustering provides high availability for services and can include shared storage, but the infrastructure cost is significantly higher than a simple RAID array.

Server virtualization abstracts hardware resources and enables VM portability, but does not inherently provide storage-level fault tolerance or data redundancy.

RAID 6 uses double distributed parity across drives, tolerating up to two concurrent disk failures without data loss. It requires only two extra drives for parity overhead, making it the most cost-effective solution specifically for data fault tolerance compared to the other options.