The best choice that supports the geographers' and hydrologists' argument is:
(Choice A) Canada and Australia have similar precipitation levels but very different amounts of freshwater resources per capita.
This choice highlights how two countries (Canada and Australia) can have similar precipitation (537 mm for both) yet exhibit significant differences in their internal freshwater resources per capita (75,795 m³ for Canada and 19,416 m³ for Australia), underscoring the argument that other factors contribute to freshwater availability.