Although Most People Can Recognize the Expressions of Happiness,sadness,fear,anger,disgust,and Surprise,why

Although most people can recognize the expressions of happiness,sadness,fear,anger,disgust,and surprise,why is this result NOT convincing evidence that we have six "basic" emotions?​

A) The expressions vary slightly from one culture to another.
B) ​People could recognize these expressions more accurately, if they were posed differently.
C) ​People could recognize these expressions more accurately if posture were added.
D) ​People can recognize other facial expressions.