Which type of death resulting from radiation exposure occurs with the highest dose?

CNS death occurs at the highest irradiative doses among the types mentioned. This fatality relates to damage inflicted to the central nervous system, which is extremely sensitive to high levels of radiation. The threshold for CNS effects typically starts at doses around 30 grays, which can lead to symptoms such as seizures, respiratory failure, and ultimately death.

In contrast, hematopoietic death generally occurs at lower doses affecting the blood-forming organs, leading to a decline in red and white blood cells; gastrointestinal death results from damage to the cells lining the intestines, which can occur at doses between 6 to 30 grays; and hematologic death, often interchangeable with hematopoietic, indicates death resulting from the failure of blood cell production but typically occurs before CNS failure in terms of dose response. Therefore, the progressive nature of the response to radiation illustrates that CNS death is contingent on a much higher radiation exposure, making it the correct answer in terms of the required dose for lethality.