Which factor does NOT increase a diver's susceptibility to oxygen toxicity?

A diver's susceptibility to oxygen toxicity is influenced by several factors, including high ambient pressure, exposure time, and even physiological elements like age and experience level. High ambient pressure, such as that encountered during deep dives, increases the partial pressure of oxygen in the body, thereby raising the risk of toxicity. Similarly, longer exposure times at elevated oxygen levels can lead to a higher risk of oxygen toxicity because the body is subjected to those levels for an extended duration.

The impact of age and experience level on susceptibility involves physiological changes and the ability to manage stresses encountered during diving. Younger divers or those with less experience may face increased risks due to less developed physiological responses and knowledge about managing diving conditions effectively.

In contrast, vitamin C deficiency does not have a direct correlation with oxygen toxicity in divers. While vitamin C is important for overall health and can affect various body functions, it is not specifically tied to the mechanisms that cause oxygen toxicity during diving. Therefore, it doesn't contribute to heightened susceptibility in the same way the other options do. This makes vitamin C deficiency the correct answer as it does not increase the risk of oxygen toxicity for divers.