C. Complements: A horse and a carriage are sold in an auction. There are two potential buyers: AND and OR. AND wants only the horse and the carriage together - she receives a utility of formula_47 from holding both of them but a utility of 0 for holding only one of them. OR wants either the horse or the carriage but doesn't need both - he receives a utility of formula_48 from holding one of them and the same utility for holding both of them. Here, when formula_49, a competitive equilibrium does NOT exist, i.e, no price will clear the market. "Proof": consider the following options for the sum of the prices (horse-price + carriage-price):