Assume the spot Swiss franc is $0.7080 and the six-month forward rate is $0.6990. What is the minimum price that a six-month American call option with a striking price of $0.6840 should sell for in a rational market? Assume the annualized six-month Eurodollar rate is 3.5 percent. (Do not round intermediate calculations. Round your answer to 2 decimal places.)