Buying or “Going Long” on a Call is a strategy that must be devised when the investor is bullish on the market direction moving up in the short term.
Buying or “Going Long” on a Put is a strategy that must be devised when the investor is Bearish on the market direction going down in the short term.
Buy or Long Straddle is considered as a non-directional strategy and is used when the underlying is expected to show large movements in either direction i.e. Upside or Downside.
