Which of the Following Statements About Yawning Is TRUE

Multiple Choice

Which of the following statements about yawning is TRUE?

A) Yawning is usually followed by a decrease in activity level.
B) One bit of evidence confirming that yawning is contagious is that about half of adults will yawn when shown videos of other people yawning.
C) Contagious yawning is rare or nonexistent in highly social primates such as macaques and chimpanzees.
D) Blind people never experience contagious yawning.