Collateral shall be:
A. Deposited with the financial guaranty insurer;
B. Held in trust by a trustee or custodian acceptable to the Commissioner for the benefit of the financial guaranty insurer; or
C. Held in trust pursuant to the bond indenture or other trust arrangement for the benefit of security holders in the form of funds for the payment of insured obligations, sinking funds, or other reserves that may be used to pay the insured obligations and trustee and other administrative fees on a first priority basis established and continually maintained pursuant to the bond indenture or other trust arrangement by a trustee acceptable to the Commissioner.