How does Part B Medicare premium vary?

Part B Medicare premiums are indeed based on individual income levels. The standard premium amount may be adjusted according to the beneficiary’s modified adjusted gross income (MAGI) from two years prior. This means that higher-income individuals are required to pay a higher premium, while those with lower incomes may qualify for a reduced premium or may even receive assistance based on their financial situations. Additionally, the income-based adjustments apply to individuals above certain thresholds, which ensures that the premiums are more equitably aligned with the beneficiaries' financial capabilities.

The notion that Part B premiums would be a single fixed amount or not vary at all does not take into account the program's design to consider income disparities among its recipients. Furthermore, age does not influence the determination of premiums, as all beneficiaries are subject to income-based adjustments regardless of their age. Thus, B captures the essence of how Part B Medicare premiums function in relation to income, making it the correct response.