Consider a market with a risk-free bond B, for which B0 = 50, B1 = 55, and B2 = 60, and a risky stock with the spot price S0 = 50. Suppose that the stock price at times t = 1 and t = 2 can follow four possible scenarios: Find an arbitrage investment strategy if there are no restrictions on short selling. Is there an arbitrage opportunity if no short selling of the risky asset is allowed