Who assists the Governor in preparing the state budget?

The Treasurer assists the Governor in preparing the state budget by providing financial oversight and ensuring that the proposed budget aligns with the state’s fiscal capabilities. The Treasurer's role includes managing state funds, collecting revenues, and advising on the financial implications of budget proposals. This position is essential for ensuring that the budget is realistic and that the state can meet its financial obligations.

The other roles mentioned, such as the National Guard, Attorney General, and Chief Justice, have specific responsibilities in law enforcement, legal representation, and judicial matters, respectively, but do not typically engage directly in the fiscal planning or budgetary process of the state. The Treasurer's unique focus on financial management makes this position crucial in the context of budget preparation, thereby validating the choice of the Treasurer as the correct answer.