Nowadays Machines Can Keep an Individual's Heart and Lungs Functioning

Nowadays machines can keep an individual's heart and lungs functioning long after the brain permanently and completely shuts down. Thus, we can have an individual whose organs are mechanically operated while he is in a coma or persistent vegetative state. To some, these facts suggest that the

A) conventional notion of death is still adequate.
B) conventional notion of death is inadequate.
C) cessation of breathing and blood flow are not signs of death.
D) conventional notion of death has always seemed inadequate.