Question: When designing a serverless web application using Lambda, what key concept must you factor into your design?

1. Serverless web applications run within the web browser of the user, so you will need to store any data the user changes directly in a database.
2. Lambda only allows you to write functions in JavaScript.
3. Lambda does not use servers, so it can only return the same request to every user.
4. Lambda is stateless, so it won't remember who a user is in between requests.

Answer: The correct answer of the above question is Option D:Lambda is stateless, so it won't remember who a user is in between requests.