Which one of the following is the fastest mass movement?

Correct option is B

Introduction
Mass movements are classified by the speed of the moving material. A Rock-fall is a form of very rapid mass movement where individual rocks or a mass of rock detach from a steep slope or cliff face and fall freely, bounce, or roll down. This free-falling action makes it the fastest type of mass movement.
Information Booster
· Mass Movement: A process where material moves down a slope under the influence of gravity.
· Speed: Rock-fall is the fastest type of mass movement.
· Mechanism: Detached rocks fall through the air with little or no interaction with other materials on the cliff face.
· Slope: Occurs almost exclusively on very steep or vertical cliff faces.
· Contrast: Other movements like creeps (slowest), slumps, and slides are much slower than free-falling rock.
Additional Points
· Rock-slide and Debris-slide: These are movements where the rock or debris slides along a relatively well-defined plane; while fast, they are generally slower than a free-fall.
· Rock-slump: A form of rotational slide that is slower than a rock-fall, characterized by a backward rotation of the moving mass.