Walk _______ the footpath, don't walk _________the road.

Walk _ the footpath, don't walk ___the road.

On, in

At, in

On, on

On, at

"Walk on the footpath, don't walk on the road."

We use "on" when referring to surfaces like roads and footpaths.

You walk on a footpath and walk on a road, not "in" or "at" them.

The preposition "on" correctly indicates that you are moving along the surface.