Unit 1: Legislation to reduce the negative externalities from soda consumption

Great article from the Guardian about the plan of NY mayor Michael Bloomberg to ban the selling of supersize drinks

http://www.guardian.co.uk/world/2012/may/31/new-york-mayor-soda-obesity

a) What negative externalities could arise from the free market sale of supersize drinks?
b) What alternative policies could the Mayor have used instead of an outright ban?
c) Comment on the likely success of the ban in reducing the market failure