Which of the following is an example of ductile deformation?

Ductile deformation refers to the ability of a material to undergo significant plastic deformation before rupture, meaning it can bend and twist without breaking. This type of deformation occurs under conditions of high stress and temperature, especially in materials that are malleable.

When considering the correct answer, bending a metal into a new shape exemplifies ductile deformation perfectly, as the metal can be manipulated significantly while remaining intact without fracturing. This ability to change shape permanently under stress indicates that the metal has undergone ductile deformation.

In contrast, breaking a rock cleanly into two pieces represents brittle deformation, where the material fails suddenly without much warning. A spring returning to its original shape after being compressed showcases elastic deformation, which is reversible rather than permanent. Lastly, rock layering forming through erosion is a geological process that involves sedimentation and is not related to how materials deform under stress. Thus, bending a metal into a new shape is the clearest example of ductile deformation.