Geometry

Question Analysis：
Focuses exclusively on the angle doubling property of intersecting-line reflections.

Key Concept Explanation：
Fundamental Theorem: The angle between initial and final paths equals twice the angle between mirrors

Step-by-Step Solution：
Given mirror angle: 25°
Apply doubling rule: 2 × 25° = 50°
Direction depends on reflection order (clockwise/counterclockwise)

Option Analysis：
A) Incorrect: Uses raw mirror angle
B) Incorrect: Incorrect calculation (40° = 25° + 15°)
C) Correct: Proper application of 2θ rule
D) Incorrect: Overcalculation (65° = 25° + 40°)

Common Mistak...