The table displays the velocity of sound in various materials.
Substance Speed
Air 344
Water 1,437
Rock 3,000
Based on the data presented in the table, which of the following boys would be able to hear a rock falling off a cliff one kilometer away? (1 point)
a boy sitting in a tree with his ear to the bark
a boy swimming in the water
a boy lying down with his ear to the ground
a boy sitting on the grass