Which of the following is an advantage of using a dry standpipe?

The use of a dry standpipe system indeed minimizes potential water damage in non-fighting conditions, which is a significant advantage. A dry standpipe is typically used in environments where the risk of freezing exists or where water in the pipes could lead to unwanted leakage and damage. Since these systems are not filled with water unless the fire department connects a hose, there is no risk of water damage when the system is not in use.

In contrast, other options present benefits associated with different systems or conditions. For instance, a constant water supply may pertain to wet standpipe systems rather than dry ones. Similarly, while dry standpipes can be easier to maintain relative to some wet systems, they may not necessarily be simpler to install. Maintenance costs may vary based on multiple factors that aren't directly tied to whether a standpipe is dry or wet, including other environmental conditions and system specifics.