Odd One Out

(i) Durable Goods : Furniture, Cupboard, Washing Machine, Fish.
Odd Word: Fish.
Explanation: Fish is perishable, while the other items (Furniture, Cupboard, Washing Machine) are durable goods.
(ii) Cost Concepts : Total cost, Average cost, Marginal cost, Selling cost.
Odd Word: Selling cost.
Explanation: Selling cost is an expense related to the sale of goods, while the other costs (Total cost, Average cost, Marginal cost) are production-related costs.
(iii) Legal Monopoly :
Patent, OPEC, Copyright, Trademark.
Odd Word: OPEC.
Explanation: OPEC is an international organization, whereas Patent, Copyright, and Trademark are legal concepts related to intellectual property rights.
(iv) Theory of Economic Welfare :
Theory of Income and Employment, Efficiency in production, Efficiency in Consumption, Overall Economic Efficiency.
Odd Word: Theory of Income and Employment.
Explanation: Theory of Income and Employment is an economic theory, while the others (Efficiency in production, Efficiency in Consumption, Overall Economic Efficiency) are specific aspects of economic welfare.
(v) Exceptions to the Law of Demand:
Giffen's paradox, Prestige goods, Price illusion, Supply of labour.
Odd Word: Supply of labour.
Explanation: Supply of labour is not directly related to the Law of Demand, while the others (Giffen's paradox, Prestige goods, Price illusion) are exceptions to the Law of Demand.