Suppose that the current stock price of Coinbase (COIN) is $350 per share. The continuously compounded risk-free rate is 1% per annum, and the volatility (i.e., the standard deviation) of COIN's returns is estimated to be 47.5% per annum. You are thinking about purchasing a put option on COIN stock with a strike price of $250 per share and an expiration date of one year from today. What is the price of this put option according to the Black-Scholes option-pricing model?

Also,

Consider a two-period binomial tree with the following characteristics:

• Each period is one year
• The current price of a non-dividend paying stock is $20 per share
• The stock can rise by 28.5% each year (i.e., u = 1.285)
• The stock can decline by 15% each year (i.e., d=0.85)
• The risk-free interest rate is 1% per annum

What is the price of an American call option on this stock with a strike price of $20 that matures in two years from today?