Which Salesforce feature should the Community Cloud consultant recommend?

Universal Containers (UC) recently built a Community for its customers. UC stores customer invoices outside of Salesforce. UC wants to allow customers to be able to search for and view their invoices immediately after creation.

Which Salesforce feature should the Community Cloud consultant recommend?
A . Chatter and Files
B . External Services
C . Files Connect
D . Files Sync

Answer: C