A skier goes down without friction on an incline that makes an angle θ=30∘ with the horizontal. The initial speed is v=5 m/s, and the distance traveled on the incline is L=20 m. Once the skier reaches the bottom of the incline, what is their final velocity?
A) 5m/s
B) 10m/s
C) 15m/s
D) 20 m/s