Why should refrigerated spaces aboard ship only be entered for a few minutes at a time?

The correct choice highlights the risk of high levels of carbon dioxide that can be present in refrigerated spaces. These spaces are designed to preserve food and perishable items, and during this process, there may be a buildup of carbon dioxide due to respiration from items stored inside or from other factors. Since refrigerated environments often have limited ventilation, the potential for elevated levels of carbon dioxide can pose significant health risks, including dizziness or unconsciousness if exposed for extended periods.

While potential low visibility, limited air supply, and extreme cold exposure are all important considerations, they do not specifically address the immediate danger posed by carbon dioxide levels. Limited air supply could be a related issue but is not as directly detrimental in the context of health hazards posed during brief entries into such spaces. In short, the primary concern revolves around the atmospheric conditions that can develop in refrigerated areas, making it crucial to limit the duration of exposure.