Where do sound waves travel faster?

through denser materials, because the molecules in a tightly packed medium collide more frequently
through less dense materials, because the molecules in a loosely packed medium collide less frequently
through less dense materials, because the molecules in a loosely packed medium collide more frequently
through denser materials, because the molecules in a tightly packed medium collide less frequently

Sound waves travel faster through denser materials, because the molecules in a tightly packed medium collide less frequently.