[单选题]
If the acceleration vector o/sugp l(vekzs4;p* w b z2ia6+f xe(qub7 v6j. pan object is directed anti-parallel to the velocity vector v 6.bq(epu7xj,
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.