Which option is NOT one of the three Rs?

• A. Replace
• B. Reduce
• C. Refuse
• D. Refine

Answer: (C)

Three Rs provide the framework for humane use of animals in research: Replace, Reduce, Refine. Replace means using alternatives to animals whenever possible, such as in vitro methods, computer models, or non-sentient organisms. Reduce focuses on using the smallest number of animals necessary to achieve scientific objectives, achieved through careful experimental design, proper power analysis, and data sharing. Refine involves altering procedures to minimize pain, distress, and suffering, and to improve welfare, for example by using better anesthesia and analgesia, improving handling, and applying humane endpoints. The option that is not part of this framework is Refuse; there is no R for Refuse in the three Rs. Refuse reflects an ethical stance, but the established framework consists of Replace, Reduce, and Refine.