Final answer:
The LD50, which represents the dose of radiation that will kill 50% of the exposed population within 30 days, is typically around 4-5 Gy for whole-body irradiation. The closest answer to the typical human LD50 among the options given is (b) 5 Gy.
Step-by-step explanation:
The question is addressing the subject of lethal doses of radiation and their deterministic effects on the human body. The lethal dose (LD50) is the amount of radiation that is expected to cause death in 50% of an exposed population within 30 days. For whole-body irradiation, the LD50 is commonly understood to be 4-5 Gy (Gray). However, it is important to recognize that individual responses to radiation can vary, and factors such as medical care post-exposure play a significant role in survival and recovery.
Regarding the options provided in the question: (a) 2 Gy, (b) 5 Gy, (c) 10 Gy, (d) 20 Gy; the closest estimate to the typical LD50 for humans is (b) 5 Gy. It should be noted that this figure can vary based on the data source and the population studied, but as a general reference, 5 Gy is a commonly accepted value for LD50 with regards to whole body irradiation.