Which of the following is a FULLY SYNTHETIC opioid analgesic?

Opioids are classified by their origin: Natural opiates (derived from opium poppy — Papaver somniferum): morphine, codeine, thebaine. Semi-synthetic opioids (chemically modified from natural opiates): hydrocodone (from codeine), oxycodone (from thebaine), heroin (from morphine), hydromorphone. Fully synthetic opioids (entirely laboratory-synthesized, no natural opiate precursor): fentanyl, methadone, meperidine (pethidine), tramadol, buprenorphine. Fentanyl is approximately 100 times more potent than morphine and is used for surgical anesthesia, breakthrough cancer pain, and chronic pain management.