Final answer:
A custodian holds or safeguards assets without fiduciary responsibility, differing from a managing agent, trustee, or executor who all have fiduciary duties toward beneficiaries or estates they serve.
Step-by-step explanation:
The correct answer to which of the following is a contractual, non-fiduciary relationship is c. Custodian. A custodian is typically involved in holding or safeguarding physical assets or investments, but they do not have a fiduciary responsibility to manage the assets for the best interest of the beneficiary, which is a key component of a fiduciary relationship. In contrast, a managing agent, trustee, and executor all have fiduciary responsibilities where they must act in the best interest of the parties they represent. The trustee has an explicit fiduciary duty to manage the trust's assets for the benefit of the beneficiaries. Similarly, an executor is responsible for administering a deceased person's will and has a duty to act in the best interest of the estate and the beneficiaries.