Which geographical condition increases the likelihood of frozen water mains?

The choice indicating that very cold regions increase the likelihood of frozen water mains is correct because temperatures consistently below freezing significantly raise the risk of water mains freezing. In these regions, the ground can remain frozen for extended periods, and if water in the pipes is not adequately insulated or if the temperature of the water itself is low, it becomes more susceptible to freezing. Additionally, water expands as it freezes, which can lead to pipe breaks and other infrastructure damage.

In very cold regions, the design and maintenance of the water distribution system must account for the lower temperature extremes. Conversely, high altitude alone does not guarantee cold enough temperatures year-round to freeze water mains; it depends on the specific climate of that altitude. Subtropical climates generally do not reach temperatures low enough for extended periods to cause freezing, while temperate zones can vary widely; they may experience colder spells but are not consistently cold enough to cause frozen water mains as frequently as very cold regions.