At a dose of 10mg, drug X lowers total cholesterol by 50 mg/dL, while a maximum drop in cholesterol of 65 mg/dL is achieved at 40mg. At a dose of 5mg, drug Y lowers cholesterol by 50 mg/dL, while maximum drop in cholesterol of 55 mg/dL is achieved at 10mg. What can be concluded about the efficacy and potency of these two drugs?

The correct answer is D because it reflects the relationship between potency and efficacy for drugs X and Y based on the information provided in the question.

Potency refers to the amount of drug needed to produce a specific effect, while efficacy is the maximum effect that a drug can produce. In this scenario, we can see that drug X achieves a maximum drop in cholesterol of 65 mg/dL at a dose of 40 mg, while drug Y achieves a maximum drop of 55 mg/dL at a dose of 10 mg. This indicates that at lower doses, drug Y is more potent than drug X because it achieves the same effect with a lower dose. However, when it comes to efficacy, drug X has a higher efficacy as it is able to achieve a greater maximum drop in cholesterol compared to drug Y.

Therefore, based on the information provided, we can conclude that drug Y is more potent, but drug X has a higher efficacy.