The phrases from the poem that use imagery to help the reader visualize the runner on the road are:
A. rocky road looms; gravel and grit
This phrase provides a strong visual image of the ground the runner is on, highlighting the texture and nature of the road.
B. heels lift and fall; knees bend and straighten
This phrase gives a clear picture of the runner's movement, allowing the reader to envision the physical action of running.
Thus, both options A and B contain imagery that helps the reader visualize the runner on the road.