The question states that optimal level of guns traded be zero. I am confused about this statement. Does this mean that there is no guns traded in the market???? no gun market in Australia??

2. Consider the market for guns in Australia. Assume that because some of these guns fall into the hands of criminals, there is a negative consumption externality. Illustrate this market on a diagram, and explain the resulting DWL from the market outcome. What is a possible government intervention from the government? Under what circumstances would the optimal level of guns traded be zero? Explain