please do it in 20 minutes please urgently... I'll give you up thumb definitely

You are a U.S.-based treasurer with $1,000,000 to invest. The dollar-euro exchange rate is quoted as $1.20=1.00 and the dollar-pound exchange rate is quoted at $1.80=1.00. If a bank quotes you a cross rate of 1.00=1.20 how can you make money? Buy at $1.20/, buy at 1.20/, sell at $1.80/ Buy at $1.80/, buy at 1.20/, sell at $1.20/ none of the other answers No arbitrage is possible