The correct answer is Option 2: Sound is a mechanical wave and longitudinal in nature.

Explanation

Sound waves traveling through air are classified by two fundamental characteristics:

Mechanical Wave: A mechanical wave is a wave that requires a material medium (such as a solid, liquid, or gas) to travel. Sound cannot travel through a vacuum because it relies on the vibration of particles (like air molecules) to transfer its energy from one point to another.

Longitudinal Nature: In a longitudinal wave, the particles of the medium vibrate parallel to the direction that the wave is traveling. As sound moves through the air, it pushes air molecules back and forth, creating alternating regions of high pressure called compressions and low pressure called rarefactions.

Why the Other Options Are Incorrect

Electromagnetic Waves (Options 1 & 4): Electromagnetic waves (like light, X-rays, or radio waves) are created by vibrating electric and magnetic fields and do not require a medium; they can travel perfectly through the vacuum of space. Sound is completely different.

Transverse Waves (Options 1 & 3): In a transverse wave, the particles of the medium vibrate perpendicular (at a 90-degree angle) to the direction of the wave's travel (like waves on a guitar string or ripples on a water surface). Sound waves in air or gases cannot be transverse because fluids do not support shear stress.