Geometry

Question Analysis：
This question combines knowledge of quadrant placement, coordinate transformation, and properties of reflection.

Key Concept Explanation:
Reflection over y = x swaps the coordinates.
It doesn’t change the distance from the origin because it’s a rigid motion.
Quadrant analysis depends on the sign of new coordinates.

Step-by-Step Solution：
(–6, 1) → (1, –6)
A. ✅ (1, –6) is in Quadrant IV (x+, y–)
B. ✅ Correct coordinates
C. ✅ Distance to origin stays the same
D. ✅ x and y are swapped
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