Guys, I'm new and i have a few questions that will sound dumb to you but.... reality is I'm not an option expert like you and teachers (as I guess you know) are NOT great So I'd really appreciate a little help . These are my difficulties: when I look at option quotes for instance on marketwatch i see for instace that a call stike 130 has a quote when the stock is at 140+ (so it seems it's not exercized) 1) does it mean that this is an european option (or an opt. that can be exercised only at maturity)? 2) in an europ. option, for instance a call, if i see the stock going up a lot and want to lock the profit can I sell short the stock at that level (so that at expiration i get the difference between the strike and the price at which I shorted)? Is it easier to just sell the option?? 3) I took some prices from marketwatch (I also attached a file) the call on citibank with 15 days to expir. stike 15, stock @4.81 is worth .04 1 week later, 8 days to expir. citi @ 4.88 the call is still worth 0.04. How come theta did not kill the price?? Are these quote updated or it's not true that theta kills the price fast in the last days??? I'm confused 4)in the black-scholes model I understand that you multiply the stock price * delta (=N(d1)) but then I do not understand the 2nd part Xe..* N(d2)... Thanks a lot guys!!!