When people use Medicare’s Plan Compare tool, they’ll see options from insurers like Humana ( HUM ), UnitedHealthcare ( UNH ), and Blue Cross ( ELV ). So how should they decide between an HMO (health maintenance organization) or PPO (preferred provider organization) plan — and whether to include prescription drug coverage?“It’s an annual requirement,” Oh said. “So, it’s important to understand that with Medicare Advantage, it’s the insurance company — not Medicare itself — that decides what benefits your pl ...