Which One of the Following Best Describes the Difference Between

Which one of the following best describes the difference between an activity and an event?

A) An activity is the completion of major project tasks,and an event focuses on the resources to be used for the task.
B) An activity avoids describing the attainment of objectives in operational terms,whereas an event does not.
C) Activity emphasizes the internal environment,as opposed to an event which emphasizes the external environment.
D) An activity is a specified set of behaviors within a project,and an event is the completion of major project tasks.
E) Activities focus on present opportunities,while events focus on potential opportunities that may not materialize.