How can the Architect meet these requirements?

Universal Containers (UC) is building a customer community and will allow customers to authenticate using Facebook credentials. The First time the user authenticating using facebook, UC would like a customer account created automatically in their Accounting system. The accounting system has a web service accessible to Salesforce for the creation of accounts .

How can the Architect meet these requirements?
A . Create a custom application on Heroku that manages the sign-on process from Facebook.
B. Use JIT Provisioning to automatically create the account in the accounting system.
C. Add an Apex callout in the registration handler of the authorization provider.
D. Use OAuth JWT flow to pass the data from Salesforce to the Accounting System.

Answer: C