B. There is not enough matter in space to transmit sound waves.
Explanation:
Sound waves are created when there is a vibration of the particles in a medium. For example, our voice is an example of sound wave: when we speak, the molecules of air around us start vibrating, producing regions of higher concentration of molecules (called compressions) and of lower concentration (called rarefactions). It is clear from this definition that sound waves can only propagate if there is a physical medium: such as a gas, a liquid or a solid, but sound waves cannot propagate through empty space.
Since space is almost empty, the correct choice is
B. There is not enough matter in space to transmit sound waves.
