Regarding the appearance and sequence of emotions in infants, which of the following statements is TRUE?

A. Emotions, such as fear and jealousy, appear in infants at the same time.
B. It is complicated and difficult to determine the onset of some emotions, and researchers hold very different views and report different findings.
C. Infants experience emotions in the following sequence: joy, pride, sadness, shame, anger, fear.
D. Researchers have reached consensus that jealousy does not emerge until after approximately 18 months of age.

B. It is complicated and difficult to determine the onset of some emotions, and researchers hold very different views and report different findings.