23. Senegal exports fish and imports fuel. The utility function and the budget constraints are: maximise U(fish, fuel) = fish * fuel m = Pfishfish + Pfuelfuel On the basis of given information determine the following: a) Marshallian demand function. Explain whether both these are normal goods. b) derive the indirect utility function c) derive the Hicksian demand function d) Explain the intuition behind the application of Roy's identity e) Derive the expenditure function