which feature separates watersheds?\no basins\no bays\no ridges\no rivers

Brief Explanations:

A ridge is a raised landform that acts as a natural boundary between different watersheds. Watersheds are areas of land where all the water that falls within it drains to a common outlet. Basins are depressions where water collects, bays are coastal inlets, and rivers are water - flowing channels within a watershed, not separators of watersheds.

Answer:

C. ridges