Which of the following provides legal authority for the disposition of a dead body?

The last will and testament of the deceased provides the legal authority for the disposition of a dead body as it explicitly expresses the deceased's wishes regarding burial, cremation, or any other specific desires concerning their remains. This document is vital in guiding the appointed executor or personal representative in making decisions that respect the decedent's preferences.

In contrast, while a living will addresses medical decisions and end-of-life care, it does not pertain to post-mortem arrangements. A power of attorney, typically designated for making decisions during a person's lifetime, generally terminates upon death and does not grant authority over the disposition of a deceased person's body. Although a death certificate is an essential document for legal purposes following a death, it does not provide authorization for how the body should be handled or disposed of. Therefore, the last will and testament stands out as the definitive source of authority in matters of body disposition.