Which of the following is not considered a long-term effect of radiation exposure?

C. Erythema is recognized as an immediate response to radiation exposure rather than a long-term effect. It refers to skin reddening, similar to a sunburn, that occurs after a significant dose of radiation. This reaction typically manifests shortly after exposure and resolves over time, making it a characteristic of acute radiation response.

In contrast, cataracts, carcinogenesis, and life span shortening are all considered long-term effects of radiation exposure. Cataracts develop over time due to the damage to the lens of the eye, which may take years or decades to manifest. Carcinogenesis refers to the process by which radiation can lead to cancer, often occurring many years after initial exposure. Life span shortening is a long-term consequence that refers to the potential reduction in life expectancy resulting from prolonged radiation exposure, with effects accumulating over time as the body incurs damage.