A futures exchange shall establish a margin management system. The margin management system should include the following contents: ① the standard and form of collecting margin from members; ② The minimum balance of the member's settlement reserve in the special settlement account; ③ Disposal method when the balance of member's settlement reserve is lower than the minimum balance stipulated by the futures exchange. The minimum balance of a member's settlement reserve shall be paid by the member to the futures exchange with its own funds. So choose ABCD for this question.