As described in subpart C of this part, applicants shall prepare the applicable environmental documentation concurrent with a proposed action's engineering, planning, and design activities. RUS shall assist applicants by outlining the types of information required and shall provide guidance and oversight in the development of the documentation. Documentation shall not be considered complete until all public review periods, as applicable, have expired and RUS concurrence, as set forth in the appropriate decision document and associated public notice, has been issued.