How should a Community Cloud consultant accomplish this task?

Universal Containers (UC) tracks customers in its Salesforce org as Contacts. UC plans to on-board a select set of existing customers to the UC community, without the need for users to self register.

How should a Community Cloud consultant accomplish this task? Select one or more of the following:
A . Use data loader to export contacts and insert as Community users
B . Use the Data Import Wizard to create users from contacts
C . Enable Person Accounts and set the accounts as Community users
D . Use the Salesforce Community user API to create users from contacts

Answer: C