Any designation to a profitable railroad pursuant to this paragraph shall comply with the second sentence of section
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(d)(4) of this title, and shall only be made upon a finding by the Association that such designation is integrally related to an offer of rail properties to a profitable railroad in the final system plan, that the goals of the final system plan require that the rail properties be operated as a part of the rail properties included in such offer, and that the implementation of such designation will not materially and adversely affect the impact of such offer on the profitability of the Corporation or any profitable railroad operating in the region. Any designation to a profitable railroad pursuant to this subsection, which amends any prior offer, shall terminate 30 days after February 5, 1976, unless, prior to such date, such profitable railroad has notified the Association in writing of its acceptance of such amendment to the prior offer.