Try explaining about some interesting course you have taken during your Bachelor's Degree, give some explanations and state how it triggered your interest in the course your are applying for. You can also explain about your internships, what you have learnt, what you were exposed to and from there draw some conclusions about how you became interested in the course you are planning to apply to.
You can also explain about some challenges you faced during you Bachelor's Degree and how you overcame it. What did you learn from those challenges? How did it impact your path?
Or, you can talk