Suppose you are a customer in the FX market and observe the following quotes for FX spot trades of BRL vs. the USD, MXN vs. the USD and MXN vs. the BRL with three dealers A, B and C: Dealer Currency Pair Bid Ask A S(MXN/USD) 19.942 19.950 B S(BRL/USD) 4.925 4.936 C S(MXN/BRL) 4.041 4.063 At these rates: You can make an arbitrage profit because the bid price with dealer C is too high by approximately 0.02. The arbitrage trade involves selling BRL with dealer C. You can make an arbitrage profit because the ask price with dealer C is too low by approximately 0.01. The arbitrage trade involves buying BRL with dealer C. You can make an arbitrage profit because the ask price with dealer C is too low by approximately 0.02. The arbitrage trade involves buying BRL with dealer C. O None of the other answers. You can make an arbitrage profit because the bid price with dealer C is too high by approximately 0.01. The arbitrage trade involves selling BRL with dealer C