Final answer:
Azure Machine Learning is the tool that simplifies AI application development on Azure, by providing a platform to build, train, and deploy machine learning models efficiently.
Step-by-step explanation:
The tool that simplifies the development of AI applications on Azure is Azure Machine Learning. This cloud-based platform allows developers to build, train, and deploy machine learning models efficiently. Using drag-and-drop machine learning designer and automated machine learning capabilities, it helps in accelerating the AI development process.
Azure Cognitive Services, on the other hand, provides pre-built AI capabilities to embed in applications. Azure Databricks is an analytics platform optimized for the Microsoft Azure cloud services platform, providing a collaborative environment for data science and engineering. Lastly, Azure Functions is a serverless compute service that allows users to run event-triggered code without having to explicitly provision or manage infrastructure.