Another more in-depth answer might sound like this: I would love to have the opportunity to be employed in a company where career growth and challenging work are common occurrences, providing me with the opportunity to utilize my core skills in assisting with the growth of the position and the company. From my prior research on your company, I can see that you routinely offer these opportunities and I know your company will value my core skills. I am really excited for the opportunity to possibly work with you for beyond five years.