The question asks about a key advantage of using ConstraintLayout in Android apps. Let's evaluate the given options: It allows for a more complicated UI hierarchy. This is incorrect. ConstraintLayout is designed to flatten* UI hierarchies by allowing complex layouts to be built with fewer nested view groups, which improves performance. It provides better performance than FrameLayout. While ConstraintLayout can offer better performance than deeply nested layouts like LinearLayout or RelativeLayout due to its flat hierarchy, FrameLayout is a very simple layout and can be highly performant for its specific use cases (e.g., displaying a single view or overlapping views). The primary performance benefit of ConstraintLayout comes from reducing nesting in complex UIs, not necessarily being universally superior to FrameLayout. It is the only layout that supports animations. This is incorrect. Many Android layouts and views support animations. ConstraintLayout does offer features for animating layout changes (e.g., with ConstraintSet), but it is not unique in supporting animations. It enables the creation of complex responsive designs efficiently. This is a key advantage. ConstraintLayout allows you to define flexible relationships (constraints) between UI elements. This makes it highly effective for building complex user interfaces that adapt well to various screen sizes, orientations, and aspect ratios, leading to responsive designs that are both powerful and efficient to implement. The correct option is: It enables the creation of complex responsive designs efficiently.