How were these records added without error?

The standard Lead Rating field has picklist values of Hot, Warm, and Cold. A list of new leads was importance without errors even though several records had the value of Unrated in the Rating field.

How were these records added without error?
A . The Restricted picklist checkbox was unchecked.
B . Field-level security was set to Visible for all profiles.
C . A global picklist value set was used to populate the picklist.
D . The Add to All Record Types checkbox was selected.

Answer: A