What is considered the most positive sign of death?

The most positive sign of death is generalized decomposition. This sign indicates that the body has entered the advanced stages of decomposition, which occurs as an inevitable process following death. Decomposition is a natural progression that starts shortly after death and is driven by various factors including bacterial activity and tissue breakdown. The presence of decomposition signifies that death has not only occurred but has also progressed significantly past the initial stages.

In the context of the other options, cardiac arrest is a critical condition that can lead to death but does not confirm it on its own, as resuscitation efforts may still be effective. Pallor mortis, the paleness that follows death, and fixed dilated pupils are early signs that might suggest someone has died, but they do not indicate the progression of decomposing bodily functions, which is characterized by generalized decomposition.