According to the Research on Detection of Deception,when Does an Observer

According to the research on detection of deception,when does an observer have the best chance of accurately detecting whether an actor is lying?

A) when the actor is also performing a difficult cognitive task
B) when the observer expects the actor to be deceptive
C) when the observer is focused on the context of the actor's behaviour rather than the behaviour itself
D) when the observer is focused on the actor's face