What if they could explain what a b-tree is, and why they are useful, but that they'd have trouble implementing one on the spot. If they told you the name of a

What if they could explain what a b-tree is, and why they are useful, but that they'd have trouble implementing one on the spot. If they told you the name of a good book they know that has an explanation of b-trees. That they read the chapter a while ago, which is why they can generally explain what a b-tree is, and that that's where they'd go if b-trees came up and they needed to write/implement one? I don't mean to imply that this wouldn't be acceptable to you. I do "know" that I've been screened out after giving an answer like this (to the extent that I can really know the reason, legally they aren't allowed to say).