Answer:
I'm pretty sure he's looking at the wall and inspecting it.
Answer:
B.) Inspecting a stone wall
Explanation:
In the first sentence we read "Something there is that doesn't love a wall" then in line 7 we read "Where they have left not one stone on a stone" so we can infer our character is referring to a wall but more specifically a stone wall "That sends the frozen-ground-swell under it."