[单选题]
An object is moving win,vg4/vv b *4ku l)uvjth constant non-zero velocity in the +x axis. The posyd7bu v ..qb /owt-v5pition versus time graph of thid-vy wb7tv o.u5 .p/bqs object is
A. a horizontal straight line.
B. a vertical straight line.
C. a straight line making an angle with the time axis.
D. a parabolic curve.
