http://7sage.com/lsat_explanations/lsat-71-section-3-question-21/
I've figured out why C) and E) are wrong, but I'm not sure how the other incorrect answers weaken the argument.
Just wanted to clarify something. For both rules in in out games are we able to make the inference that one of the two items has to be in the 'in' group and one in the out group?