Strategy - BUY PUT (details below)
Put option is bought with a strike price of a. The more bearish the investor is, the lower the strike price should be.
Profit potential is unlimited (well, not really unlimited of course as the market can not fall below zero).
Breakeven Point at Expiry
Strike price minus premium paid.
Limited to the premium paid - incurred if at expiry the market is at or above the strike a.
If the market does little then the value of the position will decrease as the option time value falls.