Which fully managed Azure offering can enable users to register, discover, understand, consume the data sources and addresses the challenges of data source discovery for the users?

Answer options:

A.Azure Data factory
B.Azure Databricks
C.Azure Cosmos DB 
D.Azure Data Catalog

Correct Answer:D
Option A is INCORRECT. Azure Data Factory is an Azure Cloud Offering that helps by performing ETL (Extract Transform Load) and ELT (Extract Load Transform). Data factory is not useful for data analysis and transformation.
Option B is INCORRECT. Azure Databricks is an analytics service based on Apache Spark and remains an apt choice for performing analysis and transformation of data on the messages picked up from IoT hub and eventually storing it in storage service.
Option C is INCORRECT. Fully managed NoSQL database service, Azure Cosmos DB, is a suitable choice for storage of analyzed and transformed IoT data.
Option D is CORRECT. Azure Data Catalog is a fully managed Azure service that helps users to register, discover, understand, consume the data sources, and addresses the challenges of data source discovery for the users.
References: 

https://docs.microsoft.com/en-us/azure/data-factory/introduction
https://azure.microsoft.com/en-us/services/databricks/
https://azure.microsoft.com/en-us/services/cosmos-db/
https://docs.microsoft.com/en-us/azure/data-catalog/