Which of the following is NOT a function of a heating oil tank?

The correct choice highlights that providing a temperature control mechanism is not a function of a heating oil tank. Heating oil tanks are designed primarily for the storage and supply of heating oil to a heating system. Their main functions include securely storing the oil, ensuring a steady supply to the heating system, and containing potential spills during delivery to prevent environmental contamination.

Heating oil tanks do not inherently regulate the temperature of the oil stored within them. While the temperature of heating oil can influence its viscosity and flow characteristics, the tank itself lacks any built-in mechanisms for temperature control. This role is usually fulfilled by external heating systems or the system that utilizes the oil, rather than the tank itself.

The other options represent essential functions of a heating oil tank: storing heating oil is its primary purpose, supplying the oil to the heating system is crucial for the system's operation, and containing spills during oil deliveries is an important feature for environmental safety and compliance with regulations.