Suppose: S = 30, k = 20, T-T = 0.5, r = 10%. Calculate the theoretical upper and lower limits of the option price If the market transaction price of the option c = 3, is there arbitrage? If it exists, write arbitrage strategy.

Further assume: S = 30, k = 20, T-T = 0.5, r = 10%. The dividend paid by the stock in the second month and the third month, calculate the present value of dividend income, and the upper and lower limit of the call option price;