Which of the Following Was NOT a Limitation of Charles

Which of the following was NOT a limitation of Charles Darwin's original studies of emotional expression?

A) Darwin only collected data regarding the expressions of people in England; he did not investigate expressions in other parts of the world.
B) Darwin relied on his acquaintances' assumptions about the emotions of the people making the expressions, rather than measuring the emotions directly.
C) Darwin's questions were phrased in a way that told observers what the expressions should look like, rather than allowing the observers to describe the expressions in their own words.
D) All of the limitations described above were present in Darwin's original studies.