What license type should an Architect recommend for the customers?

Universal Containers (UC) uses Salesforce to allow customers to keep track of the order status. The customers can log in to Salesforce using external authentication providers, such as Facebook and Google. UC is also leveraging the App Launcher to let customers access an of platform application for generating shipping labels. The label generator application uses OAuth to provide users access .

What license type should an Architect recommend for the customers?
A . Customer Community license
B . Identity license
C . Customer Community Plus license
D . External Identity license

Answer: B