If the follow up question is:
"And you can't get growth opportunities at your current position?"
Then the answer is:
"Unfortunately, no. I tried making it work to my best, but it seems that I may exercise my aspirations somewhere else, and <enter the company you're interviewing with now> appears to match with my vision and progress plan."
"Unfortunately, no. I tried making it work to my best, but it seems that I may exercise my aspirations somewhere else, and <enter the company you're interviewing with now> appears to match with my vision and progress plan."