What is a 'safety stop,' and when should it be done?

A safety stop is a critical practice in diving that involves making a controlled stop at a depth of approximately 5 meters (15 feet) for about three minutes during the ascent after completing a dive. This procedure is designed to allow dissolved nitrogen in the body, which accumulates during the dive, to safely off-gas and reduce the risk of decompression sickness, often referred to as "the bends."

Conducting this stop at the specified depth helps to stabilize the diver’s physical condition and provides an opportunity for monitoring any potential ascent-related issues. Implementing a safety stop is regarded as a standard precaution, especially after dives that exceed certain depths or durations, as it contributes significantly to diver safety.

While other options mention different types of pauses or checks, they do not accurately represent the defined purpose of a safety stop within the context of ascent procedures. Thus, the specific elements of depth and duration make this answer the most appropriate in the context of safe diving practices.