A 70 year old woman dies in a nursing home after a hea attack. The time of onset of her clinical symptomatology and the cause of death are unceain; fuhermore, the possibility of neglect is being considered. Therefore, an autopsy investigation is arranged. The forensic pathologist discovers acute thrombosis involving the posterior descending branch of the right coronary aery with resultant myocardial infarction (MI) in the posterior third of the interventricular septum. Histologically, there is coagulation necrosis with associated abundant neutrophilic infiltration. Histiocytes and lymphocytes are scanty. Which of the following is the approximate period between the onset of pain (ie, beginning of ischemic injury) and death?