Without relying on formula type of thinking ("C has two links, not one", "B mentions the word brand so it may concern brand identity"), can somebody elaborate on B's meaning?
I have a problem with B, and think that "maintain" does not equal "keep the same". "Maintenance" may include changing the logo, some features of the brand etc (=maintain the brand communication with consumers), OR may mean keeping the brand the same (=maintain the current status). To choose B, one has to extra infer that maintaining the brand means keeping the brand the same.
My problem is- with same success (extra inferring), one can draw another scenario with E. If generics cost the same, and brand is a significant power keeping the customers, then changing the brand (notice, as it is stated in the stem - not extra inferring) threatens one of the tools attracting customers - changed brand may become nothing specific, but another option among other generic brands for customers.