An *unpublished* study found it helped college students prepping for the LSAT:
http://www.nytimes.com/2012/04/22/magazine/can-you-make-yourself-smarter.html?pagewanted=all&_r=0
You can eliminate B) because the style manual tells us that we can correct w/o explanation if it's an "obvious typographical error." An obvious typo is not the same thing as an archaic spelling.
... brute force of trial and error instead of game-breaking inferences ... to do these comfortably, without error, within timeframe, upon first attempt ... to require more trial and error/brute force.
See if this method works..it does 90% of the time for me...so at the beginning of every lesson, I let the video run for 5 secs and then pause it, it buffers and does not give the error...