Before revision:  {\it   In fact, the simple and intuitively appealing expression for this measure  allows us to study the strangle's exit strategy and the corresponding optimal choices for values {\it   of delta.
After revision:  We demonstrate how this bound can be used as a quick{\it In fact, the simple and intuitively appealing expression for this measure allows us to study the strangle's exit strategy and the corresponding optimal choices for values {\it of delta.