Final answer:
The appearance and sequence of emotions in infants can be complex and varied, making it difficult to determine a specific sequence or timeline. Researchers have different views and findings on the onset of emotions in infants. vThe correct statement is c. It is complicated and difficult to determine the onset of some emotions, and researchers hold very different views and report different findings.
Step-by-step explanation:
Understanding the sequence and appearance of emotions in infants can be challenging because emotions develop and manifest differently in each individual. Some emotions, like joy and fear, may appear early on in infancy, while others, like jealousy, may take more time to emerge. Researchers have different perspectives and findings on the onset of these emotions, making it complex to determine a specific sequence or timeline.