Given the public healthcare system in New Zealand, explain the private and social costs of recreational marijuana use in New Zealand. Explain with the help of a diagram whether the equilibrium quantity of recreational marijuana use in a perfectly competitive market is too low or too high, compared to social optimum. Discuss the policy options with which the New Zealand Government can internalise the externality of recreational marijuana use on the public healthcare system. [hint: tax, the command- and-control approach, education, etc.]