[单选题]
If the position versus time qcm8bge al q a3r9i(8/zevh+ylu:8d1 gr.od9zdirca3 an(2 wf0aph of an object is a horizontal line, the object in0 wrico 2dz.d3(a9afs
A. moving with constant non-zero speed.
B. moving with constant non-zero acceleration.
C. at rest.
D. moving with infinite speed.
