Cal. Rev. & Tax. Code § 13103

Within 90 days after the mailing of the notice of the board’s action upon a claim for refund or credit, the claimant may bring an action against the board on the grounds set forth in the claim in a court of competent jurisdiction in any county or city and county in the State in which the Attorney General has an office for the recovery of the whole or any part of the amount with respect to which the claim has been disallowed. The Attorney General shall defend the action.