It came to our attention thanks to users P Adams and Andrew Mandelbaum, that LSAC provided the wrong solution key for a problem from a past test (PT 28, S2, Q9) which is featured in the Assignment Lesson Intro 1 module in the LSAT App, question 22. We posted the walk-through and the correct solution key in the problem's discussion thread, which can be viewed on the web via http://www.arcadiaprep.com/discussions/735/pt_28_s2_q9to_prepare_for_fieldwork_exactly_four_different_researchersa_geologist_/