Which Azure service is responsible for detecting anomalies in account activity?

The correct choice is Azure Defender for Storage, which is a comprehensive security solution that incorporates features to protect and monitor the security status of your storage accounts. One of its key capabilities is anomaly detection in account activity. This ensures that any unusual patterns of access, such as unexpected spikes in requests or access from unfamiliar IP addresses, are identified in real time, allowing administrators to respond quickly to potential security threats.

In contrast, Azure Storage Account Security Feature primarily focuses on configuring network and security settings for the storage account but does not specifically provide anomaly detection. Azure Key Vault is dedicated to managing secrets and protecting cryptographic keys, whereas Azure Monitor is a broader monitoring service that encompasses various Azure resources but does not specialize in detecting anomalies specifically for storage accounts. Thus, Azure Defender for Storage stands out as the service designed specifically for the purpose of detecting anomalies in account activity within Azure storage services.