Which additional service should you deploy to support the VPN authentication?

You are planning an Azure Point-to-Site (P2S) VPN that will use OpenVPN.

Users will authenticate by using an on premises Active Directory domain.

Which additional service should you deploy to support the VPN authentication?
A . a certification authority (CA)
B. a RADIUS server
C. an Azure key vault
D. Azure Active Directory (Azure AD) Application Proxy

Answer: B

Explanation:

Reference: https://docs.microsoft.com/en-us/azure/vpn-gateway/point-to-site-about