Official Explanation:
Last year, one woman contracted food poisoning, sued, and won a large settlement that attracted a great deal of attention. This year, there have been "copycat" suits, that is, suits motivated primarily by a desire to achieve a similarly large settlement. We know that all eleven Chinese restaurants have been sued: we don't know whether all those suits are legitimate --- that is, whether anyone actually suffered from food poisoning.
(E) is the credited answer. Since the suits are "copycat" in nature, this suggests that at least some of the Chinese restaurants have been entirely innocent with respect to giving patrons food poisoning. Nevertheless, these restaurants have been sued, and are therefore unfairly subject to legal expenses.
The other four answers make the fallacious assumption that all the suits this year are justified. This is precisely what (B) states, and if that were true, there would be reason to suspect that (D) is true. Choices (A) and (C) not only make this fallacious assumption but also expand it to an even more general rule about Chinese restaurants. None of these are justified conclusions.