OK, the answers are:
3: 70-200 L
5: White balanced to match Canon, version of 4
So the 3C answers correctly identified the L. But to those who got it right, can you honestly state that you did not use DOF or perspective subtleties to help you in identifying the L shot?! State your correction criteria by referring others to your identifying characteristic in the photo which led to your decision, so that they can try to see if they might be able to identify the L also, using your criteria. I know I look at these shots, and the differences between photos are subtle, but I rather doubt I could consistently find the L based on claims of 'better color'. Even though I consistently put the photos in the same sequence each time, we have one participant whose answers changed each time...and to me (any by my own efforts) 'chance' more than 'consistent identification' seems to be the rule.