Member States shall carry out systematic scrutiny of the commercial documents of undertakings taking account of the nature of the transactions to be scrutinized. Member States shall ensure that the selection of undertakings for scrutiny gives the best possible assurance of the effectiveness of the measures for preventing and detecting irregularities under the system of financing by the Guarantee Section of the EAGGF. Inter alia the selection shall take account of the financial importance of the undertakings in that system and other risk factors.