A physics class is experimenting with sound waves in the hallway of their school. Student A is holding his physics textbook out in front of him at one end of the hallway. At the other end of the hallway, 100 m away, two students (student B and student C) are listening for the sound of the textbook hitting the floor, ready to raise a hand as soon as they hear the sound. Student B is standing up, while student C is laying down with her ear pressed against the floor. When student A drops the textbook, student C is the first to raise her hand. Explain why student C hears the sound before student B. 1) Student C was laying on the ground, and sound travels faster through lower air near the floor 2) Student C has her ear pressed against the cold floor, sound travels faster at cold temperatures 3) Student C has her ear pressed against the solid floor, and sound travels faster in solids than in gases (like air) 4) The speed of sound is constant, so student C just raised her hand faster