This question is quite neat, and I do believe it would fall under the hard category. You need to have a good foundation on your geometrical figures. For example, 1) The figure seems like a rectangle. Given the restrictions of the problem, does it have to be a rectangle? No, we could have a square as well, and you might recall that squares are that perfect quadrilateral, so it’s always nice to work with squares and that’s why I chose a square as my first case. 2) It says that BC=CD, so we have for sure an isosceles triangle, but what if allow the measurements of BC to be equal to BD? We would have a “perfect triangle” i.e. an equilateral one. That’s why I chose that case and wrote down “Suppose BC=4”. Notice that we got that B would be the correct answer. Do we need to have an equilateral triangle? Not really, we only know that it is an isosceles triangle, so what if we make BD>BC? That’s why I chose a second case. Hope the picture makes sense, and if not, let me know and I’ll do my best to give a more thorough explanation.

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