Final answer:
The correct answer is b) Register it with the government.
Step-by-step explanation:
The correct answer to the question is b) Register it with the government.
When someone owns a cylinder that has contained a refrigerant, it is important to register it with the government. This is because refrigerants are considered hazardous materials, and the government wants to ensure that they are handled and disposed of properly. By registering the cylinder, the government can keep track of who has the refrigerant and ensure that it is disposed of safely.