In Human Behavioral Economics,a Choice to Do an Activity Means

In human behavioral economics,a choice to do an activity means

A) choosing not to do the next best activity.
B) choosing not to do a more desirable activity.
C) evaluating that activity versus an alternative group of activities.
D) that activity should be put at the top of a "to-do" list.
E) that activity must have an observable characteristic to be valid in a behavioral sense.