What is the key difference between an application and a service principal?

A. Service principals exist in the directory where the application is created, where application objects exist in each Azure AD tenant where the application is used.

B. Application objects are templates that exist in every directory where an application is used. They’re used to create service principals that can be customized in each directory.

C. Application objects exist in the directory where the application is created, where service principal objects exist in each Azure AD tenant where the application is used.