When sound waves propagate through a medium, the physical quantity transmitted is primarily energy.

Option-1: Matter Only

This option is incorrect because although sound waves do cause vibrations in the particles of a medium, it is the energy of these vibrations that is being transmitted, not the matter itself.

Option-2: Energy Only

This is the correct answer. Sound waves carry energy as they propagate through a medium. This energy is transferred from one particle to another through the mechanical vibrations of the particles.

Option-3: Energy and Matter Only

This option is partially correct as sound waves do involve the transmission of energy. However, it incorrectly includes matter as a transmitted physical quantity. It is the energy carried by the vibrations of matter that is being transmitted, not the matter itself.

Option-4: Energy, Momentum, and Matter

This option is incorrect because sound waves primarily transmit energy, not momentum or matter. While sound waves do carry momentum, it is secondary to the primary transmission of energy. Additionally, matter is not physically transmitted by sound waves but rather remains in place while the energy of the wave moves through it.

In conclusion, the correct option is 2 - Energy Only.