An ambulance’s warning signal has a frequency of $600\,\text{Hz}$. The speed of sound is $330\,\text{m s}^{-1}$. The ambulance moves at a constant velocity of $25\,\text{m s}^{-1}$ towards an observer. What overall change in the observed frequency occurs from when the ambulance is far behind the observer to when it is far in front of the observer?
- A$49\,\text{Hz}$
- B$84\,\text{Hz}$
- C$91\,\text{Hz}$
- D$98\,\text{Hz}$