(1) A warehouse operator's bond; or

(2) Obligations that are unconditionally guaranteed as to both interest and principal by the United States, in a sum equal at their par value to the amount of the bond otherwise required to be furnished, together with an irrevocable power of attorney authorizing AMS to collect, sell, assign and transfer such obligations in case of any default in the performance of any of the conditions required in the licensing agreement; or

(3) An irrevocable letter of credit issued in the favor of AMS with a term of not less than two years; or

(4) A certificate of participation in, and coverage by, an indemnity or insurance fund as approved by AMS, established and maintained by a State, backed by the full faith and credit of the applicable State, which guarantees depositors of the licensed warehouse full indemnification for the breach of any obligation of the licensed warehouse operator under the terms of the Act. If a warehouse operator files a bond or financial assurance in the form of a certification of participation in an indemnity or insurance fund, the certification may only be used to satisfy any deficiencies in assets above the minimum net worth requirement as prescribed in the applicable licensing agreement. A certificate of participation and coverage in this fund must be furnished to AMS annually; or

(5) Other alternative instruments and forms of financial assurance approved by AMS as may be prescribed in the applicable licensing agreement.