Final answer:
A codicil is a legal amendment to a will that allows for changes or additions without rewriting the entire will. It needs to be formally executed like a will. The concept differs from a living will, which focuses on a person's end-of-life medical decisions.
Step-by-step explanation:
A codicil is A. A legal amendment to a will. It is a document used to make changes or additions to an existing will, which allows the person who has created the will (testator) to make minor adjustments without needing to write a new will entirely. Just like a will, a codicil also needs to be executed with the same formalities, such as being witnessed.
Comparatively, a living will or an advance directive is a legal document stating a person's wishes concerning life-prolonging medical treatments, possibly including a Do Not Resuscitate (DNR) Order or appointing a health care proxy when they are incapable of making decisions due to incapacitation. Both a traditional will and a living will reflect a person's desires regarding their assets and health care, but serve different purposes and are separate legal documents.