The correct answer is Vacuum.

 Key Points

• Sound is a form of energy produced by the vibration of an object or body.
• Sound travels through air particles and requires a medium to travel.
• A vacuum, as we all know, is an empty space devoid of all matter.
• It is a space where the gaseous pressure is significantly lower than atmospheric pressure.
• Sound is a mechanical wave, which requires a medium to travel. In a vacuum, sound cannot travel because there are no molecules to vibrate or transmit the wave. Therefore, sound cannot travel in a vacuum.

  Important Points

• Mechanical Wave:
  • Mechanical waves are waves generated by vibrations in matter, transferring energy through a material medium.
  • Not all waves are like this. For example, electromagnetic waves like visible light are not mechanical because they can travel through the vacuum of space to reach us from the Sun.
  • Mechanical waves include water waves, sound waves, seismic waves, and many more.
  • Like all waves, mechanical waves also have peaks, crests, and troughs.
  • They also have a frequency, which is the number of waves passing per second, and a wavelength, which is the distance from one crest to the next, or from one trough to the next.