Answer: Client-side encryption with Azure Key Vault

Correct answer is **C. Client-side encryption with Azure Key Vault**. This method is not supported for encrypting data at rest in an Azure Databricks workspace. Here's why the other options are supported: - **A. Server-side encryption with customer-managed keys in Azure Blob Storage**: Azure Blob Storage supports server-side encryption where data is automatically encrypted before being written to disk and decrypted when read. - **B. Encryption using Azure Managed Disk Encryption**: This method helps protect data on Azure managed disks by encrypting the disk volumes. - **D. Transparent Data Encryption (TDE)**: TDE encrypts the storage of an entire database by using a symmetric key called the database encryption key, protecting the data stored in the database files.

Author: LeetQuiz Editorial Team