When the price of a good changes, the substitution effect can be found by comparing the equilibrium quantities purchased A. on the old budget line and the new budget line. B. on the original indifference curve when faced with the original prices and when faced with the new prices. C. on the new budget line and a hypothetical budget line that is a shift back to the original indifference curve parallel to the new budget line. D. on the new indifference curve.