Final answer:
Samuel and Lisa's relationship can be characterized as toxic due to Samuel's behavior of berating, belittling, and criticizing Lisa when they are alone.
Step-by-step explanation:
Based on the description provided, Samuel and Lisa's relationship would be characterized as c) Toxic. In a toxic relationship, one or both partners engage in behaviors that are emotionally harmful to the other. This includes actions like berating, belittling, and criticizing, which can undermine someone's self-esteem and well-being. Despite how the relationship might appear to others on the outside, it is the actual dynamics between the couple that define the nature of their relationship. A supportive, healthy, or harmonious relationship would not involve one partner consistently mistreating the other. It's essential to acknowledge the seriousness of this behavior, as emotional abuse can have long-lasting and detrimental effects on an individual's mental health.