What must be ensured about each anchor in a twin tension system?

In a twin tension system, it's crucial that either anchor can independently support the load in the event of failure. This characteristic ensures redundancy and safety, which are paramount in rescue operations. If one anchor fails, the other must be capable of taking on the entire load without compromising safety.

This design allows for a more robust system, as rescuers can have confidence that the operation can continue safely even if one of the anchors experiences a failure. The integrity of the whole system relies on each anchor's ability to handle the load independently, which makes the configuration reliable in high-stakes scenarios.

Other options may suggest important aspects of anchor use, such as the need for load sharing or the requirement of multiple anchors, but they do not capture the essential redundancy that is critical for safety in this type of rigging system. The independence of each anchor is what enhances the overall security of the rescue operation.