Answer:
None of the states.
Step-by-step explanation:
Since XYZ Advisers is a federal covered adviser, it implies that it is registered with the Security and Exchange Commission (SEC) but not registered with any of the states. Therefore, only the SEC has its registration that it can revoke.
However, it is compulsory for the XYZ Advisers or any other adviser carrying out a business in any state to notify the State in which it is carrying out a business. This is to enable the relevant State to carry out an investigation and issue an order against the adviser whenever the the Administrator of a State received a complaint against a federal covered adviser. But the state still does not have the registration of the federal covered adviser it can revoke.
Therefore, none of the State Administrator(s) has the authority to revoke XYZ Adviser's registration.