Option 3: (A) - (IV), (B) - (III), (C) - (I), (D) - (II) -> MPS (Marginal Propensity to Save) represents the change in savings per unit change in income (IV). MPC (Marginal Propensity to Consume) represents the change in consumption per unit change in income (III). APS (Average Propensity to Save) represents saving per unit of income (I). APC (Average Propensity to Consume) represents consumption per unit of income (II). The key distinction is that 'Marginal' refers to changes (incremental), while 'Average' refers to the total ratio. -> correct