Virginia Code § 38.2-4306 requires HMOs to offer preventive care, coordinated by primary care physicians (PCPs), focusing on health maintenance. Option A (well-baby checkups), option B (immunizations for children), and option D (physical examinations) are standard preventive services—e.g., growth monitoring, vaccines, and annual exams—covered at no cost under ACA-aligned plans (Virginia Code § 38.2-3440). Option C (experimental surgery) is not preventive; it’s a treatment, often excluded or requiring special approval due to its unproven nature, not a PCP’s routine role. The study guide likely lists HMO preventive benefits with examples (e.g., flu shots), contrasting them with non-preventive interventions like surgery, making C the exception.