When Researchers Tested the Ability to Recognize Facial Expressions of Emotion,how

When researchers tested the ability to recognize facial expressions of emotion,how could they have improved the accuracy of recognition?​

A) Use photos of real people in real situations instead of expressions posed by actors.
B) ​Tell people to answer quickly, based on their first impulse.
C) ​Let observers use their own labels, instead of giving them six choices.
D) ​Pose frightened people looking to the side and sad people looking down.