A water-filled long tube has a tap attached at its lower end, as illustrated. A tuning fork is made to vibrate above the tube, and the water is then permitted to flow out slowly from the tube. As the water level falls, a louder sound is produced at regular intervals. The difference in water level between successive louder sounds is $32\,\text{cm}$. What is the wavelength of the sound in the tube?
- A$16\,\text{cm}$
- B$32\,\text{cm}$
- C$64\,\text{cm}$
- D$128\,\text{cm}$