From the case given in the question, it is clear that Liz is having troubles with her team members because of (E) weak position power.
Positional power refers to the type of power that the individual has by being in a leadership position in an organization. Because Liz is at the same position levels in the organization as her team members, they are less inclined to respect her authority despite of her current team leader position. Although (C) is a possible answer, it is incorrect because the case study above does not mentioned the quality of Liz’s relationship with her team members – since referent power refers to interpersonal skills that lead to a person’s influence with other people.