Which of the following is a key principle of democracy?

Accountability is indeed a key principle of democracy because it ensures that elected officials and public servants are answerable to the people they serve. In a democratic system, those in power have a responsibility to operate transparently and justify their decisions, actions, and use of public resources. This principle promotes good governance, encourages civic participation, and fosters trust in governmental institutions.

While integrity, efficiency, and popularity may have relevance in various contexts, they do not encapsulate the core essence of democracy to the same extent as accountability. Integrity relates to ethical behavior, efficiency refers to how well resources are used, and popularity may often pertain to public opinion but does not guarantee effective governance or represent democratic ideals. Thus, accountability stands out as essential in maintaining the health and functioning of a democratic society.