Final answer:
A drainage divide is a high elevation line that separates neighboring drainage basins, directing water to different watersheds or river systems. The correct option is a.
Step-by-step explanation:
A drainage divide is a ridge or strip of high ground that separates one drainage basin from another. If you consider the land's topography, the divide is the highest elevation in an area, directing water flow into different basins. Picture this as the crest of a hill or a mountain range; rain falling on one side of it will flow into one river system, while rain on the other side will flow into another river system altogether.
The drainage basin itself is an area of land where water from rain and snowmelt drains downhill into a body of water, like a river, lake, reservoir, or ocean. This concept is essential to understanding hydrological cycles and water resource management.
Hence, Option a is correct.