Answer by emphasizing your greatest strengths against the advertised position. What do you pride yourself on the most? Which strengths will be, in your opinion, most beneficial to this role? Which will contribute to the company's success? Which strengths make you indispensable?
"I am a hard worker who does not hesitate to go above and beyond to ensure successful completion of projects, and I am more than willing to take on duties beyond my original job scope. I sincerely believe the company's success is my success."