Which coastline type tends to produce more resistant rocks that protrude as headlands?

The correct choice is rooted in the geological and structural characteristics of different coastline types. A discordant coastline is where the rock layers are oriented at an angle to the coastline, often leading to variations in rock resistance against erosion. This means that some rock types will erode more quickly than others, resulting in the formation of headlands and bays. The more resistant rocks, which are less susceptible to erosion, will project out into the sea, forming headlands. This creates a landscape where the softer rock erodes away, creating sheltered bays, while the harder rock forms prominent structures along the coast.

In contrast, a concordant coastline has rock layers that run parallel to the shoreline, which typically results in more uniform erosion and a smoother coastline without distinct headlands. Urban coastlines focus on human development and may not directly relate to geological features that produce headlands. Rugged coastlines, while they can include headlands, generally describe a physical landscape rather than a specific geological arrangement, and may not necessarily produce headlands derived from resistant rock types in the same predictable manner as a discordant coastline does.