A police car, moving at speed $$108\,\text{km h}^{-1}$$, approaches a truck moving at $$72\,\text{km h}^{-1}$$ in opposite direction. The natural frequency of the siren of the car is $$800\,\text{Hz}$$ and the surrounding temperature is $$27^\circ\text{C}$$. The frequency heard by the truck driver as the car passes him

A

remains unchanged

B

decreases nearly by $$232\,\text{Hz}$$

C

increases nearly by $$231\,\text{Hz}$$

D

decreases nearly by $$260\,\text{Hz}$$