You are designing a distributed application for Azure.
The application must securely integrate with on-premises servers.
You need to recommend a method of enabling Internet Protocol security (IPsec)-protected connections
between on-premises servers and the distributed application.
What should you recommend?

A.
Azure Access Control

B.
Azure Content Delivery Network (CDN)

C.
Azure Service Bus

D.
Azure Site-to-Site VPN

Explanation:
IPsec can be used on Azure Site-to-Site VPN connections. Distributed applications can used the IPSec VPN
connections to communicate.
https://msdn.microsoft.com/en-us/library/azure/dn133798.aspx