In reference to trust funds, which of the following statements is correct? O a. Investment trust funds are fiduciary funds used to account for multigovernmental external investment pools sponsored by a governmental agency. b. Private-purpose trust funds are fiduciary funds used to account for resources that are held for the benefit of parties outside of the governmental agency O c. Pension trust funds are fiduciary funds used when a government acts as trustee for a defined pension plan for a governmental entity O d. All of the above are correct