Suppose the market price of a European put option on a non-dividend paying stock is smaller than the lower bound given by Xe-r*(T-t) St. In general, how does an investor achieve arbitrage profits?

1. Buy puts, long shares, and buy risk-free bonds
2. Buy puts, long shares, and borrow at the risk-free rate
3. Buy puts, short shares, and buy risk-free bonds
4. Write puts, short shares, and buy risk-free bonds
5. Write puts, long shares, and borrow at the risk-free rate