In asking this question, the hiring manager is looking for you to succinctly convey what sets you apart from the other candidates. Think of your most impressive and unique strengths that closely relate to the job description and use those to pitch yourself in a way that clearly illustrates the skill set and qualities you bring to the table.

My analytical horsepower sets me apart from other candidates. For example, I imagine all of your candidates can create robust Excel-based financial models. However, I can also see and articulate the business story behind the numbers to influence decision-making. During a major food-chain deal, I conducted the due diligence necessary to come up with the right multiple that my superiors should consider based not only on raw data but also on what was the best way to position the assets we were selling. My strategy resulted in a more profitable deal.