Final answer:
The master radioactive materials license is issued to the NRC (Nuclear Regulatory Commission), which oversees the possession and use of radioactive materials in the United States.
Step-by-step explanation:
The master radioactive materials license is issued to the NRC (Nuclear Regulatory Commission).
The Nuclear Regulatory Commission has the authority to issue licenses for the possession and use of radioactive materials in the United States.
The NRC ensures that licensees comply with regulations to protect public health and safety from potential risks associated with radioactive materials.