FERNS - if 1 then E is the second letter; if 0 then E is the first letter. from EERIE - 1, one of the first two Es must be correct because the RIE are excluded from ARRAY - 0, FLAIR - 0, CRANE - 0; respectively. From FERNS, the RNS are eliminated as possible from ARRAY - 0, CRANE - 0, GOALS - 0; respectively. So if FERNS - 1 then both F and E cannot be it so it must be the E and if FERNS - 0 it cannot be the second E so E must be the first from the logic just stated.