Alina has an intense migraine, so she goes to a local emergency room in an effort to obtain fast pain relief. The ER doctor, Dr. Anwar, prepares an injection for Alina. When Dr. Anwar begins to inject the drug into Alina’s vein, and not her muscle, Alina asks if that is safe. Dr. Anwar assures Alina it is safe, so Alina agrees to receive the injection. Within 6 hours, Alina’s arm becomes gangrenous at the injection site, and Alina has to have her arm amputated. Alina sues the drug manufacturer. At trial, the drug manufacturer presents proof that the Federal Drug Administration approved the drug for injection into veins. What is this defense an example of?