Question: Best reference to check if a medication is lactose-free. A. AHFS Drug Information → Excellent for therapeutic uses, dosing, interactions, but does not focus on excipients. B. USP DI Volume II → Patient counseling resource; not excipient-focused. C. Red Book → Pricing and product availability; not excipients. D. Martindale → Provides detailed information on drug formulations and excipients (even though it's best known for foreign drugs, it also lists inactive ingredients). Need Assignment Help?