Upvote:5
Based on the socks pattern and what I can make out of the hat pin, this appears to be the Argyll and Sutherland Highlanders of Canada (Princess Louise's), pictured here during the funeral for Corporal Nathan Cirillo:
The claim is made in the comments that the cap badge here is different than shown on Wikipedia. Wikipedia is clearly in error here (or out of date). Here is a photograph of Cpl. Nathan Cirillo, of the Argyll and Sutherland Highlanders of Canada (Princess Louise's) standing guard in Ottawa prior to his murder. Note the cap badge.