[单选题]
An object slides down a frictionless ijo4dzz.rk 6:o k;tci *nm v nkd :l6pt3lcx./k+ af: ilco2vz9)clined plane. At the bottom, it has a speed of 9.80 m/s. Wv69daf/2mc: lk)t pkn3zo:l .l cvi+ xhat is the vertical height of the plane?
A. $19.6 \; m$
B. $9.80 \; m$
C. $4.90 \; m$
D. $2.45 \; m$
