Final answer:
The most likely cause of Suzanne's rampant caries is drug-induced xerostomia option (B).
Step-by-step explanation:
The most likely cause of Suzanne's rampant caries is B. Drug-induced xerostomia.
Drug-induced xerostomia refers to a condition where a person experiences a decreased flow of saliva as a side effect of certain medications. This can lead to a dry mouth, which creates an ideal environment for the growth of bacteria and can result in rampant tooth decay.
In Suzanne's case, her medication chlorpromazine (Thorazine) is an antipsychotic that can cause xerostomia as a side effect. Her poor oral hygiene and difficulty holding down a job may contribute to her inability to maintain proper dental care, further increasing her risk of developing rampant caries.