The question asks about a key advantage of using ConstraintLayout in Android apps. Let's evaluate each option: It allows for a more complicated UI hierarchy. This is incorrect. ConstraintLayout is designed to flatten* UI hierarchies, meaning it allows you to create complex layouts with fewer nested view groups, which generally improves performance. It provides better performance than FrameLayout. While ConstraintLayout is generally performant, especially for complex layouts where it reduces nesting, 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 in all scenarios. It is the only layout that supports animations. This is incorrect. Many Android layouts and views support various types of animations. ConstraintLayout does offer powerful 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 major advantage of ConstraintLayout. It allows developers to define flexible relationships (constraints) between UI elements, making it highly effective for building complex user interfaces that adapt well to various screen sizes, orientations, and aspect ratios. This leads to responsive designs that are both powerful and efficient to implement. The correct option is: It enables the creation of complex responsive designs efficiently.