Because the left portion of the top horizontal bar is thicker than the one of the object, which may still allow the latter pass through that particular part of the aperture at the expense of violating the rules. And besides, the horizontal bar at the center of figure B appears to be out of aligning with the one of the top/bottom view. Remember that exact dimensions with the object snug-fitting at the hole is what you'll need to look for.
I suggest that you get the 3D model unshade before having it rotated. That will help a bit when attempting to correlate its projections with the answers.