(1) If the corporation is required under subsection (a) of this section to commence proceedings under this section with respect to a plan or, after issuing a notice under this section to a plan administrator, has determined that the plan should be terminated, it may, upon notice to the plan administrator, apply to the appropriate United States district court for a decree adjudicating that the plan must be terminated in order to protect the interests of the participants or to avoid any unreasonable deterioration of the financial condition of the plan or any unreasonable increase in the liability of the fund. If the trustee appointed under
subsection (b) disagrees with the determination of the corporation under the preceding sentence he may intervene in the proceeding relating to the application for the decree, or make application for such decree himself. Upon granting a decree for which the corporation or trustee has applied under this subsection the court shall authorize the trustee appointed under
subsection (b) (or appoint a trustee if one has not been appointed under such subsection and authorize him) to terminate the plan in accordance with the provisions of this subtitle. If the corporation and the plan administrator agree that a plan should be terminated and agree to the appointment of a trustee without proceeding in accordance with the requirements of this subsection (other than this sentence) the trustee shall have the power described in
subsection (d)(1) and, in addition to any other duties imposed on the trustee under law or by agreement between the corporation and the plan administrator, the trustee is subject to the duties described in
subsection (d)(3). Whenever a trustee appointed under this subchapter is operating a plan with discretion as to the date upon which final distribution of the assets is to be commenced, the trustee shall notify the corporation at least 10 days before the date on which he proposes to commence such distribution.