i'd go Agholor.
San Francisco has given up the most fantasy points to Running Backs this season. But SFF gave up 799 rushing yards with 5 touchdowns and an additional 526 receiving yards with 4 touchdowns. Blount won't have a lot of role in the passing game, so he wouldn't fully take advantage of SFF defense.
San Francisco has given up the 12th most fantasy points to Wide Receivers this season. But consider that Agholor has scored touchdowns in three consecutive games and has five touchdowns total. And Blount two touchdowns total; one rushing and one receiving.