Final answer:
The Prescription Drug Marketing Act is the legislation that effectively banned the selling, purchasing, and trading of prescription samples, which was enacted to ensure that they are only used by authorized individuals and to protect consumers.
Step-by-step explanation:
The act that banned the selling, purchasing, and trading of prescription samples is b) The Prescription Drug Marketing Act. This legislation was enacted in 1987 and is designed to prevent the diversion of prescription drugs from legitimate commercial channels. Its provisions are specific to the distribution of prescription drug samples and prohibit the sale, purchase, or trade of such samples. An important aspect of the law is the establishment of safeguards to ensure that prescription drug samples are used only by those authorized to receive them, thus protecting consumers from potential harm.