agency shall mail and, if possible, email a copy of the Proposal Document to all affected Indian Tribal Governments, including those that withdrew from the process. At a minimum, the document shall go to the Tribal leader and all members of any elected Tribal governing body. The agency shall follow up to confirm receipt of the document. After these steps have been completed, the Proposal Document shall be published in the Federal Register, subject to the provisions of section 107. (b) Public comment period The agency shall provide a period of not less than 90 days after publication in the Federal Register for comments on the Proposal Document. A 30-day extension shall be granted upon request by any member of any of the affected Indian Tribal governing bodies. (c) Preliminary decision After expiration of the comment period, the agency shall prepare a preliminary decision letter, signed by the head of the agency. The letter shall state the decision to proceed or not proceed with the activity, the decision’s rationale, any changes in the proposal made in response to comments, and any points where the decision conflicts with the expressed requests of any of the affected Indian Tribes. It shall particularly address why the decision was made to disregard any such requests. The agency shall mail and, if possible, email a copy of the letter to all affected Indian Tribal Governments, including those that withdrew from the process. At a minimum, the letter shall go to the Tribal leader and all members of the Tribal governing body. The agency shall follow up to confirm receipt of the letter. (d) Final decision The agency shall provide a 60-day period following the issuance of the preliminary decision letter for response by the affected Indian Tribes. Thereafter, the agency shall notify in writing, signed by the head of the agency, the affected Indian Tribal Governments, including those that withdrew from the process, of the agency’s final decision. 105. Documentation and reporting (a) Official consultation record The