The correct option is (c).
Explanation
Sound waves are mechanical, longitudinal waves that propagate through a material medium (solid, liquid, or gas). The propagation occurs via the vibration of particles back and forth parallel to the direction of the wave, creating alternating regions of varying density and pressure.
Statement-wise Analysis:
- Statement 1 is Incorrect: A compression is a region in a longitudinal wave where the particles of the medium are crowded together. Consequently, this is a region of high pressure and high density, not low pressure.
- Statement 2 is Correct: A rarefaction is a region where the particles of the medium are spread apart. This results in a region of low pressure and low density.
- Statement 3 is Correct: As sound moves through a medium (like air), the oscillating particles create fluctuations in the medium's physical properties. Therefore, sound propagation can be visualized and analyzed as either density variations or pressure variations moving through the medium.
Key Takeaway:
Sound propagates in air as a longitudinal wave consisting of compressions (high pressure, high density) and rarefactions (low pressure, low density).