[单选题]
A cart starts from rest 31canl bb99bzs6sn cwm u5y:13) f (e)pcm 9l/bsmnd+zzgduin59dg:and accelerates at $4.0 \; m/s^2$ for 5.0 s, then maintain that velocity for 10 s, and then decelerates at the rate of $2.0 \; m/s^2$ for 4.0 s. What is the final speed of the car?