Which of the following is a style of condenser?

The choice of air-cooled as a style of condenser is correct because air-cooled condensers utilize ambient air to remove heat from refrigerants or other fluids. In these systems, a fan is used to force air over the condenser coils, allowing the heat to dissipate into the atmosphere. This method is widely used, particularly in smaller refrigerating systems and residential air conditioning units, due to its simplicity and lower initial cost compared to other cooling methods.

Concerning the other options, solar cooled does not specifically refer to a recognized style of condenser but rather indicates a broader concept of using solar energy for cooling, which may involve different technologies. Geothermal cooled relates to systems that use the earth's temperature to facilitate cooling, typically more associated with heat pumps rather than stand-alone condensers. Thermal cooled is not a standard term in the context of condenser types and could create confusion as it doesn't distinctly describe a specific cooling process used in condensers. Thus, air-cooled is the most accurate and widely accepted classification among the given choices.