Income-based' definition of sustainable development prescribes that: a. The 'nominal income' from man-made capital should not be declining over a period of time; b. The 'real income' from man-made and natural capital should not be declining over a period of time; c. 'Nominal income' from natural capital should not be declining over a period of time; d. Current nominal Net Domestic Product (NDP) should not be declining over a period of time