Which statement correctly defines a gas main and a gas service line?

Which statement correctly defines a gas main and a gas service line?

• A. The main is the smaller pipe that connects to a customer's building.
• B. The service line is the larger primary pipe.
• C. The main is a mid-size line inside the building.
• D. The main is the large primary pipe; the service line is the smaller line that connects the main to a customer's building.

Answer: (D)