Final answer:
The appropriate action is to report Mark's behavior to the charge nurse to address potential medical issues and ensure patient safety, rather than focusing on the behavior of taking the cola which is secondary.
Step-by-step explanation:
The most appropriate response to Mark's behavior, a 32-year-old patient with schizophrenia who has been found consuming excessive amounts of cola and displaying an increase in auditory hallucinations and confusion, is B) Report Mark's behavior to the charge nurse. This action is necessary for several reasons. It ensures that Mark's increased fluid intake and change in mental status are medically evaluated since they could be signs of physical health issues, such as diabetes insipidus or psychogenic polydipsia, both of which are not uncommon in patients with schizophrenia. Reporting this incident allows for a thorough assessment of Mark's current treatment plan and the need for potential medical intervention. It's also crucial to document these observations to provide Mark with the best possible care and to protect other patients' belongings. While it's important to address Mark's theft behavior, prioritizing his health and the safety of other patients is essential in this situation.