You work for a company that has a variety of on$-$premises applications critical to its operations. The company wants to provide external users, such as partners and clients, with access to these applications, and the IT team is exploring different solutions.

In this scenario, which of the following services is defined as an on$-$premises service that allows external customers to engage with on$-$premises applications?

Active Directory domain controller

Azure AD Pass$-$through

Azure AD Application Proxy