Final answer:
Option D, which includes holding drills, conducting retraining, and updating procedures, represents examples of maintaining emergency preparedness for the disposition of radioactive materials. These actions are crucial for ensuring a high level of safety and preparedness in emergency situations.
Step-by-step explanation:
The correct answer to the question of maintaining emergency preparedness in relation to disposition of radioactive material is D. holding drills, conducting retraining, and updating procedures. These options represent proactive and structured approaches to ensuring safety and preparedness in the event of a radiation-related emergency. Conducting drills allows individuals to practice and become proficient in emergency response protocols.
Retraining ensures that relevant personnel remain up-to-date on the latest safety procedures and technologies, such as the use of Geiger counters, scintillators, and dosimeters for measuring radiation. Updating procedures ensures that all practices are in line with the current safety standards and legislation. All these are part of a comprehensive emergency preparedness plan which is essential for the safe handling and disposition of radioactive materials, thus maintaining the resilience of critical national infrastructure.