MS Option [4]

American call options written on Microsoft's common stock are trading for $8. They carry a strike price of $100, and expire 6 months from today. Microsoft does not pay dividends. At present, its stock price is $104. Hence, the calls are $4 in the money.

The annualized six-month risk free rate is 10%. Find an arbitrage opportunity (free lunch) in these numbers and explain how you would exploit it.