The solution simply identify each graph. I could only identify the first graph (K), how can we tell which graph is which by looking just at it?
Dukerio What do you mean by the volatility having bigger impact than r? If as T increases, the more likely the option to go in-the-money, why not a linear relationship? Why is it increasing slowly? And vice versa for the sigma. As for r, why did it not touch the y-axis? Why is it flatter than the rest? Like you, I also wondered what would the graphs look like for a put option, but my guess is they all flipped except for sigma and time.
when u say "direct-direct", you mean obvious, right? hehe so r has a less 'direct' relationship to option price, therefore less steep. (hmmm...) madness.
