Under Medicare Part D, a plan's formulary must generally include:

Why A is correct

Part D plans maintain formularies — lists of covered prescription drugs — that must include at least two drugs in each therapeutic category and class. This ensures beneficiaries have a meaningful choice within each treatment class and that the plan cannot restrict an entire class to a single product. Plans are not required to cover every FDA-approved drug, but they must meet CMS formulary standards, including coverage of all drugs in six protected classes. The protected classes receive even stronger formulary protection.

Why the other options are wrong

• B) The formulary standard is at least two drugs per class, not a single cheapest drug; restricting to one would fail the requirement. The two-drug minimum prevents a single-product monopoly.
• C) Plans are not required to cover every FDA-approved drug; formularies are selective by design while meeting the two-per-class standard. Formularies are selective by design while still meeting the class standard.
• D) The two-drug-per-class rule is an automatic plan-design standard; it is not triggered by beneficiary requests. The two-per-class rule is an automatic plan-design standard, not a response to individual beneficiary requests.

Memory hook

Part D formulary = at least two drugs per class, guaranteed. Plans pick the list, but never narrow a class to a single choice.