Concept:GNP at cost is the total output value after making allowance for depreciation of capital.Explanation:Start with the total expenditure figure, which represents GNP at market price.From the given data, total expenditure is £80,000μ.Depreciation is given as £6,000μ.To find GNP at cost, subtract depreciation from expenditure:GNP at cost=£80,000μ−£6,000μ.GNP at cost=£74,000μ.Answer:£74,000μ (Option C).