[单选题]
If the acceleration vector of an :9ba 7cja32;ti oaf06v qg qkhobject is directed ant.d ybrvps9w;lt u, +i,i-parallel to the velocity vector yr+.,p v;l,b9 iudwts,
A. the object is turning.
B. the object is speeding up.
C. the object is slowing down.
D. the object is moving in the negative x-direction.
