| Hot water heaters used in potable water systems may have multiple heat sources, such as an electric heating element and a jacket water heated tube bundle. What is the primary purpose of such an arrangement? |
| A) Allow the designated backup heat source to be used in the event of failure of the designated primary heat source, whether in port or underway. |
| B) Allow jacket water to be used in port and electricity to be used while underway. |
| C) Allow both the heat sources to be used when the demand for hot water is high, whether in port or underway. |
| D) Allow electricity to be used in port and jacket water to be used while underway. |
