Except as provided in subsection (b) of this section, a loan may not be guaranteed under this subchapter unless, before the closing of the loan, it is submitted to the Secretary for approval and the Secretary grants approval.

The Secretary may exempt any lender of a class of lenders listed in section 3702(d) of this title from the prior approval requirement in subsection (a) of this section if the Secretary determines that the experience of such lender or class of lenders warrants such exemption.

The Secretary may at any time upon thirty days’ notice require loans to be made by any lender or class of lenders under this subchapter to be submitted to the Secretary for prior approval. No guaranty shall exist with respect to any such loan unless evidence of the guaranty is issued by the Secretary.