As usual, your list of options does not include my referred answer.
However, A is the least likely and B is the most likely.
Why do I say B is likely:
We have just had the Amberley altercation with the Australian BoM. The BoM now claim that the station "could" have moved, but they don't know and anyway it is secret, so it needs correcting.
We have had New Zealand going to court to try and disprove that they were increasing the wraming in their "official" temperature dataset. How did they get out of that? Well, they claimed that they did not have an official dataset. Note that they did not claim they were not warming it up just that the sceptics had the name wrong. http://wattsupwiththat.files.wordpress.com/2010/08/nz-niwa-adjustment.png?w=1050
Then we have the various US examples. The 1930s vary in temperature, usually getting cooler as time goes on.
We have the published USHCN adjustments.
Plus various other examples.
So what are we to make of your comment: "(mostly, presumably, very smart people) aren't catching that fact."? Some here deny it but there are now "multiple lines of evidence" as the climatologists would say. Who are the real deniers?
I do not think this is a concerted attempt by scientists to defraud anyone just a bad outbreak of confirmation bias.