Consider a four-month put futures option with a strike price of 50 when the risk-free interest rate

Question:

Consider a four-month put futures option with a of 50 when the risk-free interest rate is 10% per annum. The current futures price is 47. What is a lower bound for the value of the futures option if it is
(a) European
(b) American?
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.