Which of the following layers can be transformed into shape layers?

The option that states vector layers can be transformed into shape layers is correct because vector layers inherently consist of scalable graphics created through mathematical equations. This allows them to maintain quality at any size and makes them well-suited to be converted into shape layers, which are also based on vector graphics.

When vector layers are transformed into shape layers in Adobe After Effects, they gain additional functionality, such as the ability to easily manipulate individual path points, apply various effects, and utilize more flexible animations. This transformation leverages the unique properties of vector graphics, allowing animators to take full advantage of the program's capabilities to create complex animations and visual designs.

In contrast, text layers, raster layers, and adjustment layers have different characteristics and limitations. Text layers can be converted into shape layers, but this option focuses specifically on vector layers. Raster layers are made up of pixel data, which doesn’t lend itself to the same type of manipulation as vectors. Adjustment layers serve a different purpose altogether, as they are used to apply effects to layers beneath them and cannot be converted into shape layers.