; (ii) bonds, notes, and debentures of the Commodity Credit Corporation described in section 4 of the Act of March 8, 1938 ( 15 U.S.C. 713a–4 ); (iii) bonds and other obligations of the Tennessee Valley Authority described in section 15d of the Tennessee Valley Authority Act of 1933 ( 16 U.S.C. 831n–4 ); and (iv) the obligations of the United States Postal Service described in section 2005 of title 39, United States Code