Geometry

Question Analysis:
This question probes a deeper understanding of reflection properties beyond just coordinate swapping.
The main focus is invariant properties and geometric relationships under reflection over y = x.

Key Concept Explanation:
Reflection over a line preserves:
Distance (isometry)
Angle
Orientation may reverse
The line of reflection is the perpendicular bisector of the segment connecting point and image.

Step-by-Step Solution:
A. x/y are swapped → ✔️ True by definition
B. On opposite sides unless on the line → ✔️ Geometrically accurate
C. Segment PP' ⟂ y = x → ✔️ Always true for reflection
D. Distance to origin preserved → ✔️ Reflection is isometric
E. P = P' → ❌ Only true if P is...