The dollar interest rate is 5% (continuously compounded) and the yen rate is 1% (continuously compounded). Consider

Question:

The dollar interest rate is 5% (continuously compounded) and the yen rate is 1% (continuously compounded).
Consider an at-the-money American dollar call that is yen-denominated (i.e., the call permits you to buy 1 dollar for 120 yen). The option has 1 year to expiration and the volatility is 10%. Let n = 3.
a. What is the price of a European call? An American call?
b. What is the price of a European put? An American put?
c. How do you account for the pattern of early exercise across the two options? Exchange Rate
The value of one currency for the purpose of conversion to another. Exchange Rate means on any day, for purposes of determining the Dollar Equivalent of any currency other than Dollars, the rate at which such currency may be exchanged into Dollars...