Among the most enduring of all horrors is the prospect of a slow, painful death. Those who witness the protracted terminal illness of a friend or relative often view the eventual death more as a relief than a tragedy.

But to make life-or-death decisions on behalf of a dying person unable to communicate his or her wishes is to enter a moral and legal minefield. Could a doctor be sued for withholding treatment and allowing someone to dieor for not allowing him or her to die？ Could it ever be lawful to withhold food and water？

Legal moves are afoot which may settle these questions. Recently, a group on voluntary euthanasia proposed legislation to make documents known as "Advance Directives", or Living Wills, legally binding.

An Advance Directive sets out the kind of medical treatment a person wishes to receive, or not receive, should he or she ever be in a condition that prevents them expressing those wishes. Such documents, much in vogue in the US and some Commonwealth countries, are becoming increasingly popular in Britain.

A clear distinction must be drawn between actions requested by an Advance Directive, and active euthanasia, or "mercy killing". A doctor who took a positive step such as giving a lethal injection-to help a patient die would, as the law stands, be guilty of murder or aiding and abetting suicide, depending on the circumstances.

An Advance Directive, however, requests only passive euthanasia: the withholding of medical treatment aimed solely at sustaining the life of a patient who is terminally ill or a vegetable. The definition of medical treatment, in such circumstances, can include food and water. The enforceability of the Advance Directive stems from the notion, long accepted in English law, that a person who is both old enough to make an informed decision and compos mentis, is entitled to refuse any medical treatment offered by a doctor, even if that refusal leads to the person's death. A doctor who forces treatment on a patient against his or her wishes is, therefore, guilty of an assault. Case law exists in the US and several Commonwealth countries that extends this right of autonomy over one's life to patients who write an Advance Directive refusing treatment and subsequently lose their previously made instructions any differently.

It will be a relief over the death of a friend or a relative if the friend or relative dies from ______.

A．a traffic accident

B．an acute infectious disease

C．heart attack

D．a three-year coma (昏迷)