A natural gas service regulator is normally set to deliver pressure from:

The role of a natural gas service regulator is to control and maintain the pressure of natural gas being delivered to appliances. Typically, a service regulator is designed to reduce the high-pressure gas from the supply line to a safe and usable level for residential appliances.

The correct answer indicates that natural gas service regulators are generally set to deliver pressure within the range measured in inches of water column (W.C.). The acceptable delivery pressure is often between a few inches of water column up to a maximum of 7 inches W.C., which is suitable for most residential appliances. This range ensures that gas appliances operate efficiently and safely without the risk of exceeding their designed pressure limits.

The other options include measurements that exceed typical delivery pressure requirements for residential use or use units such as ounces, which are generally not applicable in the context of gas pressure regulation. Thus, the understanding that regulators maintain pressure around 7 inches W.C. aligns with the operational standards for safe and efficient natural gas supply.