[单选题]
An object slides down a fric aa /;c.)p6lyr:tl ynvtionlesw5 ry3y ai yiopj+cmc69lj *2.s inclined plane. At the bottom, it has a speed of 9.80 m/s. Wci3a *i95py6mwy .y lj+ro j2chat is the vertical height of the plane?
A. $19.6 \; m$
B. $9.80 \; m$
C. $4.90 \; m$
D. $2.45 \; m$