###Rationale: B i.e. Fixed dilated pupil not responding to light Cooling of body & rigor mois is a sign of molecular or cellular death. - Somatic (systemic, clinical or brain) death is cessation of spontaneous breathing, circulation and brain activity (as indicated by flat isoelectric EEG, deep unconsciousness with no response to external stimuli or internal need). Surest sign of brain stem death is fixed dilated pupil not constricting (responding) to light.Q

###Answer: OPTION B IS CORRECT.
###Question: Surest sign of brain stem death
###Options:
A. Absent Doll's eye reflex
B. Fixed dilated pupil not reacting to light
C. Cheyne Stokes breathing
D. Decerebrate posture
