Thanks for your good answer, Sanchit. Those also are what I could image to make the response as quick as possible. But until you build a first vertical slice based on the architecture and test it, it is not 100% sure that response time will be guaranteed, except you have positive experiences on building similar systems. At first, I didn't know how to convince the evaluator of my approach. As you passed with good score, I'll do the same way.
Thanks again!