The Comptroller General may, in carrying out this section, request information from and access to any relevant documents from any person registered under paragraph (1) or (2) of section
1603
(a) of this title and each employee who is listed as a lobbyist under section
1603
(b)(6) of this title or section
1604
(b)(2)(C) of this title if the material requested relates to the purposes of this section. The Comptroller General may request such person to submit in writing such information as the Comptroller General may prescribe. The Comptroller General may notify the Congress in writing if a person from whom information has been requested under this subsection refuses to comply with the request within 45 days after the request is made.