I agree, you'll only know the answer if you've taken the time to learn about the specific concepts being tested.
I suppose what I'm surprised about is that a large number of developers haven't taken the time to learn (or have since forgotten) the theory around these particular concepts.
I aced an Advanced Algorithms course at a major public university last semester, and I don't recall learning about B-trees. I mean, I usually have pretty good retention of things I learn, and the rest of the "test" was easy enough, and I'd expect to at least think "that sounds familiar" about anything that's come up in a class, but even after I looked up B-trees, I grasped the concept fairly quickly, but it didn't seem like anything I'd learned before.
I wonder if I legitimately just forgot about B-trees, or if my algorithms courses just didn't cover them.
I suppose what I'm surprised about is that a large number of developers haven't taken the time to learn (or have since forgotten) the theory around these particular concepts.