What is not in V1, and what cannot be left out?
Answer it out loud before you open anything. The value of the flags below is in comparing them to what you actually said — including whether you asked who uses it before naming what you would build it with.
The situation behind the question
A stakeholder for the online store says "let's do an MVP" and then lists twelve features. A developer says "MVP means we can skip tests and security for now." The interviewer asks you to draw the line.
What it is really testing
Whether the candidate can tell simplification from omission: an MVP drops features and simplifies flows, but some things — correctness of money, basic security, the invariants — cannot be left out without the MVP proving nothing.