Which of the following are the three basic types of utilities, EXCEPT:

Utilities are essential services that are provided to meet the basic needs of a community or an individual, and they typically fall into three main categories: water, electrical, and gas. Each of these utility types plays a critical role in the daily functioning and convenience of residential and commercial structures.

Water utilities supply clean drinking water, which is vital for health and sanitation. Electrical utilities provide the power necessary for lighting, heating, cooling, and operation of appliances and machinery. Gas utilities, often providing natural gas, are used for heating and cooking.

Structural systems, while crucial to the integrity and functionality of buildings, do not fall under the category of utilities. They relate more to the physical framework and support system of a building, including the materials and techniques used in construction. As a result, the correct answer identifies structural systems as the exception among the choices listed, clearly distinguishing them from the essential utility services that support everyday life.