Which One of (A) -(D) Has Been Presented as a Central

Which one of (a) -(d) has been presented as a central reason for thinking that suicide is incomprehensible?

A) It is impossible to know what suicide means.
B) It is impossible to know what kind of experiences corpses have.
C) Nobody has adequate experience of being dead.
D) Desiring to die presupposes that being dead is always better than being alive.