How did you come to choose your career?
Interviewers ask this question to determine whether you intentionally pursued your career or fell into it. However, this question is not asking whether you are satisfied with your career. It is possible for someone to fall into their career and still have career satisfaction. However, if this opportunity opens the door for you to pursue a preferable career, it might be worth mentioning. They even advertise that you can switch careers internally in their efforts to reduce attrition. "At BlackRock, You Can Change Career Paths Without Leaving the Company. Employees Can Develop Transferable Skills. Internal Networking Opportunities Are Endless. Personal Interests Can Become a New Career Path. Development Programs Put a Focus on Learning. Managers Actively Help With Career Transitions."
Be transparent and show that you have recognized the opportunities that BlackRock has to offer you. However, if you are dissatisfied with your career and are hunting for any job anywhere, it will probably be spotted. For example, when what you say is inconsistent with how you say it (your tone, facial expressions, or mannerisms), it is commonly considered an indication of limited emotional intelligence or burnout syndrome. It also suggests a lack of self-awareness.
"I learned long ago that if you are good at something and enjoy doing it, you should pursue it. So, I chose my career because I was doing it before I got paid to do it."