'Unless the number of individuals in a group is quite small, or unless there is coercion or some other special device to make individuals not in their common interest, rational, self-interested individuals will not act to achieve their common or group interest'. a) Comment on the statement and describe the economic theory the statement refers to. (8.5 Marks] b) What is the evidence in favour of the 'zero contribution thesis' and what is the evidence contradicting it? Use four examples from the literature. {9 I Ila-Junk