Which of the following is NOT a type of tank farm layout?

The type of tank farm layout referred to as hexagonal is not commonly recognized or utilized in the standard configurations for tank farms. The traditional and more widely accepted tank farm layouts include horseshoe, parallel, and in-line/side-by-side arrangements.

The horseshoe layout allows for efficient use of space and facilitates easy access for transportation and operational activities. Parallel layouts enable the placement of tanks in a manner that maximizes space while maintaining operational efficiency. In-line or side-by-side arrangements also optimize land use while allowing for straightforward management of the tanks.

By contrast, a hexagonal layout does not typically conform to the practical requirements of fluid management, tank accessibility, and operational safety that are essential in fuel system design. Thus, recognizing that the hexagonal arrangement is not a traditional tank farm layout clarifies why it is selected as the answer in this context.