Final answer:
The correct MAR entry for morphine administration is "Administer morphine 5 mg Q4H PRN for pain." This clearly specifies the drug, dosage, frequency, and reason for administration as needed for pain.
Step-by-step explanation:
The correct format for the medication administration record (MAR) when a nurse receives a verbal order from the provider to administer morphine 5 mg every 4 hours subcutaneously for severe pain as needed is "Administer morphine 5 mg Q4H PRN for pain." This entry includes all the necessary information: the drug name (morphine), the dosage (5 mg), the frequency (every 4 hours, abbreviated as Q4H), the route (subcutaneously, which is assumed as it has been verbally stated), and the reason for administration (PRN for pain, indicating it should be given as needed for pain relief).