Final answer:
Spent fuel rods are not considered low-level radioactive waste since they consist of high-level radioactive material that requires stringent storage methods. Contaminated tools, protective gear, and cleaning rags are examples of low-level waste.
Step-by-step explanation:
The student’s question pertains to identifying which item listed is not considered low-level radioactive waste. Low-level radioactive waste typically includes items that have been contaminated with radioactive substances but do not include high-level waste such as spent fuel rods. Items like contaminated clothing, tools used in plant maintenance, rags used to clean water from the reactor, and contaminated protective gear are all examples of low-level radioactive waste. On the other hand, spent fuel rods are a form of high-level radioactive waste, due to their dangerous levels of radioactivity from unstable nuclei, transuranium elements like plutonium and americium, and unreacted uranium isotopes. These require very stringent handling and storage methods, often involving cooling in pools of water followed by storage in special outdoor containers. Therefore, the correct answer to the student's question is A. spent fuel rods.