Final answer:
The correct answer is option b. The fastest type of mass movement is a 'Rockslide' where large blocks of rock break off and slide down the slope rapidly, often causing significant destruction.
Step-by-step explanation:
Mass movement refers to the downward and outward movement of rock and soil on a slope due to gravity. Among the options provided, the type of mass movement that is generally the fastest is b) "Rockslide". Mass movement can range from extremely slow to very rapid; each type has different characteristics and speeds.
Creep, which is a very slow movement of soil down a slope, is so gradual that it can be difficult to observe directly. Slump is a form of mass movement that occurs when a coherent block of earth or rock moves downhill along a curved surface, which is somewhat faster but still not as rapid as a landslide or a rockslide.
Landslide can refer to a broad range of movements, including rock falls and the rapid movement of debris flows. However, the fastest among these is generally a rockslide, which is a very rapid downslope movement of rock. When a rockslide occurs, large blocks of rock break off and slide down the slope, often at great speeds, with the potential for significant destruction.
Therefore, the correct option for the fastest type of mass movement listed is b) "Rockslide".