If I am playing a xylophone with a large, professional ensemble, what am I a member of?\nOptions:\n- museum\n- abc book\n- planet\n- orchestra\n- high school band
Let's be accurate as possible and think first.
orchestra
At orchestra a musical instrument like a xylophone can be played.

If I am playing a xylophone with a large, professional ensemble, I am a memeber of an orchestra.

.

So, the answer is orchestra