What might cause this?

The architect has a requirement to create a criteria-based sharing rule based on the customer Social.. up the rule in Contact Sharing, the field is not shown on the list of available field.

What might cause this?
A . The field has been configured for encryption.
B. The architect does not have permission to Compliance fields.
C. The architect’s profile does not have field level Security (FLS) for this field.
D. fields with validation rules are not available for sharing rules.

Answer: A