Final answer:
Prescription opioids contribute to the greatest number of deaths.
Step-by-step explanation:
The drug that contributes to the greatest number of deaths among the options provided is Prescription opioids. Prescription opioids include drugs like Oxycodone, Vicodin, and methadone. The opioid epidemic in the United States has led to a significant increase in the abuse and overdose of prescription painkillers, leading to a higher number of deaths compared to other drugs like heroin, cocaine, and methamphetamine.