12. A 10-kHz sound wave is emitted by a stationary source toward an object moving 17 m/sec toward the source. What is the frequency of the wave reflected by the moving object as detected by a detector at rest near the source? (Assume the sound speed is 340 m/sec.) (A) 1.05 × 10⁴ Hz (B) 1.1 × 10⁴ Hz (C) 1.15 × 10⁴ Hz (D) 1.2 × 10⁴ Hz (E) 1.25 × 10⁴ Hz