In this task, You are given an open-domain question that can be answered based on factual information. Your task is to provide \*short\* answer (in a few words only) for the given question. The short answer can be one or more entities or it can also be boolean \*yes\* or \*no\*.

[Q]: where was the first motte and bailey castle built
[A]: northern Europe


[Q]: who took the picture of the windows xp background
[A]: Charles O'Rear


[Q]: what kind of telescope is the chandra observatory
[A]:
X-ray telescopes