阿娣是 Far West Imports 的营销者。该公司打算推出一款新的智能手机应用来帮助客户更轻松地订购商品，她是这个项目的负责人。在 Google 的建议下，该公司的开发团队已经整合了多项功能来提升转化量，但营销副总裁坚持要评估购物车和结账功能的效率。 他们可以使用哪项 Google 服务来测试应用的界面和功能？

Firebase A/B Testing is the correct choice because it is a Google service specifically designed for testing different versions of an app's UI and features to determine which performs best. This directly addresses the marketing VP's request to evaluate the efficiency of the shopping cart and checkout features. SplitMetrics and Optimizely are third-party A/B testing tools, not Google services. While Google Analytics 360 can track user behavior and conversions, it is an analytics platform, not a tool for conducting A/B tests on app interfaces and features.