Why do you want to work at our company?

To answer this question correctly, you must know your career goals, and how you fit in the job role offered to you. Read the JD entirely and tell the recruiter how you fulfill all the requirements. Study about the company, talk about the work and the positives of working there such as enhanced learning, teamwork, working with experts. One tip is that if you are not interested in the position, then there is no idea of taking it to that level. It will decrease your motivation level to be there with complete intend.