I would think that a good answer showcases your knowledge. E.g. if you knew a lot about relational databases, this is a time to apply the knowledge.
It's also good if you show the ability to see trade-offs where they exist. E.g. the trade-offs for a relational database vs. something else might be familiarity / time to implement, vs. ease solving some type of situational performance problem.
It's also good if you show the ability to see trade-offs where they exist. E.g. the trade-offs for a relational database vs. something else might be familiarity / time to implement, vs. ease solving some type of situational performance problem.