Meredith’s income expansion path connects all of the optimal bundles of bottled water and bus rides for each income level. Points A, B, C, D, and E are optimal consumption bundles associated with budget constraints BC₁ through BC₅. Where both bottled water and bus rides are normal goods, the income expansion path is upward-sloping. At incomes higher than that shown at the budget constraint BC₄ and to the right of bundle D, bus rides become inferior goods, and the income expansion path slopes downward.