Question 4 is problematic. Answer choice B may be the strongest answer, but E could also be viewed as necessary. We don't know how old Macaques are (the time period may only encapsulate one generation), so if the author is trying to prove that they can adopt and PASS ON new patterns of social behavior, this seems to heavily point towards passing the behavior to subsequent generations. If that is the case, it is necessary that the pattern will persist over several generations if the case is being used to prove the conclusion by the author. B is stronger due to ambiguity around what "pass on" and "several generations" means, but otherwise it is VERY close.