Why Might It Be Particularly Useful for Observers to Be

Why might it be particularly useful for observers to be able to rapidly detect the gaze direction of people expressing fear, compared to other emotions?

A) Fear is generally a difficult emotion to recognize, so being able to contextualize it will be informative for the observer
B) The observer can quickly locate the stimulus based on the expresser's gaze direction and prepare to respond if necessary
C) Fear is the only truly social emotion, and, as such, must be spread rapidly through the group
D) Fear is evolutionarily the oldest emotion state so it is not under the control of the expresser as much as other emotions
E) All of the above