Final answer:
Naloxone (Narcan) option (B) is an opiate antagonist that can reverse respiratory depression caused by opioid overdose, such as from morphine.
Step-by-step explanation:
The drug with the potential to reverse the respiratory-depressant effect of an opioid like morphine is Naloxone (Narcan) option (B). This medication is an opiate antagonist that rapidly counteracts the effects of opioids by binding to opioid receptors without activating them, which then displaces the opioid molecules and reverses their effects, particularly respiratory depression, which is a common cause of overdose deaths. Naloxone is especially crucial because opioids can significantly slow down or stop a person's breathing, and it helps the person wake up and continue breathing while awaiting emergency medical treatment.