A currency is currently worth $0.80 and has a volatility of 12%. The domestic and foreign risk-free

Question:

A currency is currently worth $0.80 and has a volatility of 12%. The domestic and foreign risk-free interest rates are 6% and 8%, respectively. Use a two-step binomial tree to value a) a European four-month call option with a strike price of $0.79 and b) an American four-month call option with the same strike price

Strike Price
In finance, the strike price of an option is the fixed price at which the owner of the option can buy, or sell, the underlying security or commodity.