In a dialogue about a drug's efficacy, Heather says the drug is effective, Mike says it is not. Which statement about their disagreement is most supported?

• A. Heather and Mike disagree about whether the drug is safe.
• B. Heather and Mike disagree about whether the drug is effective.
• C. Heather and Mike disagree about the price of the drug.
• D. Heather and Mike agree on the drug's effectiveness.

Answer: (B)

Disagreement here centers on a claim about how well something works. Heather says the drug is effective, while Mike says it is not. That means they are arguing about the drug’s efficacy—the truth value of whether it works as intended. The dialogue doesn’t mention safety or price, so those concepts aren’t the source of their disagreement. In short, their disagreement is about whether the drug is effective.