Eagletron's current stock price is $10. Suppose that over the current year, the stock price will either increase by 100% or decrease by 50%. Also ,the risk-free rate is 25% ( EAR).

a) what is the value today of a one-year -at- the -money . European put option on Eagletron stock?

b) what is the value today of a one-year European put option on Eagletron stock with a strike price of $20?

c) suppose the put options in parts a and b could either be exercised immediately , or in one year. What would their values be in this case?