Under what conditions can water contribute to CZ?

The correct choice highlights the significance of both water depth and sound speed in determining whether water can contribute to the acoustic environment, specifically to the characteristic known as CZ or Convergence Zone.

For water to contribute to CZ, the depth must be adequate to facilitate the necessary sound speed profile. The sound speed in water is also influenced by temperature, salinity, and pressure. For this scenario, the DSC (Deep Sound Channel) is important because it indicates a layer within the ocean where sound can travel long distances with minimal dispersion. If the sound speed exceeds the near-surface velocity, it means that sound waves can become trapped in this channel, leading to more efficient propagation.

In essence, the interplay of sufficient depth and an appropriate sound speed profile is crucial for achieving the conditions necessary for effective sound propagation and for the existence of a Convergence Zone. Other conditions mentioned, such as temperature, salinity (saltwater), or contamination levels, do not directly address this specific acoustic phenomenon, making them less relevant for this scenario.