[单选题]
An object is moving with c8o .nge/ v5+n6:g, un pkilwcyonstant non-zero velocity in the +x axis. The p3)8r jqjs oc)4r-r: tancic(cosition versus time grq8a3r( ts):)ncrccj oci-4 jraph of this 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.
