Over the coming year, Ragworts stock price might drop from $100 to $50, or it might rise to $200. The one-year interest rate is 10%.

1. What is the delta of a one-year call option on Ragwort stock with an exercise price of $100?
2. Use the replicating-portfolio method to value this call.
3. In a risk-neutral world, what is the probability that Ragwort stock will rise in price?
4. Use the risk-neutral method to check your valuation of the Ragwort option.
5. If someone told you that, in reality, there is a 60% chance that Ragworts stock price will rise to $200, would you change your view about the value of the option? Explain.