Ethics question confusion, explained, question, indicate, security

ikoreaii

in Schweser Exam1 morning vol 1 Question 6......(the trader trading tax benifits for her mother while other clients possessing the security as well)The schweser indicates A as best option (she has not violated any law) but B option does indicate a violation of III B fair dealing which i thought should be applied. Schweser has only explained wrt II B (Option C) that it is not a market manipulation-which is absolutly true. but .Can anyone clear my confusion cuz i think she has not treated her clients fairly...(the same benifit would also be available to them hinting me of violation
thanks