When a Researcher Asks Whether Evidence Exists That the Facial

When a researcher asks whether evidence exists that the facial expression for sadness is universal, what do they mean?

A) Is there evidence that sadness is expressed similarly across human cultures?
B) Is there evidence that all mammals are capable of experiencing and expressing sadness?
C) Is there evidence that most cultures display sadness so long as they have a word for it?
D) Is there evidence that globalization has caused sadness to become widespread in the last century?