Briefly Outline the factors that motivated you to apply for this position?

Without sounding canned or rehearsed, a good reply here should include some information you've gained in researching the company. Be specific, like noting that you're interested in the progressive atmosphere for which the company's known or that you're interested in the direction in which the company's headed, and then give specific examples. Impress the company by showing them you've done your reserach, are interested in the company itself and intend to pursue a career, not merely land a job.