A block, initially at rest, slides down an inclined plane at an angle of 30 degrees with the horizontal. The block is placed at a vertical distance of 6m above the bottom of the inclined plane. The coefficient of kinetic friction between the block and the plane is 0.25. Which of the following most nearly gives the velocity of the block after it has traveled 3m?

a. 4.08 m/s
b. 3.84 m/s
c. 4.15 m/s
d. 3.98 m/s