Welcome to your interview.
The question is on your right: Virtual DOM and Reconciliation. Take a moment with it first.
Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.
Explain the concept of the Virtual DOM in modern frontend frameworks and how the reconciliation process optimizes browser rendering.