Retail containers of 81 mg aspirin must have special warnings for use in children and cannot contain more than:

The correct answer reflects the regulatory requirement specified for retail containers of 81 mg aspirin, particularly regarding child safety. The U.S. Food and Drug Administration (FDA) has established guidelines that limit the quantity of certain medications in retail containers to reduce the risk of accidental overdose in children.

In the context of 81 mg aspirin, which is often used for cardiovascular health, the specific limitation to no more than 36 tablets is to ensure that a child would not have access to a harmful quantity if they gain access to the medication without supervision. This is particularly important because aspirin is associated with Reye's syndrome in children, a serious condition that can cause liver and brain damage.

By keeping the package size limited, the regulations aim to enhance safety, ensuring that the risk to children is minimized while still making the medication accessible and effective for adult use. Therefore, the correct and safe limit for retail containers of 81 mg aspirin is indeed 36 tablets, ensuring compliance with federal guidelines aimed at safeguarding young children from potential harm.