Final answer:
After initiating restraints on a combative patient, a nurse must obtain a physician's order within 1 hour to ensure that the use of restraints is medically necessary and appropriate.
Step-by-step explanation:
When a nurse applies physical restraints to a combative patient who has exhibited aggressive behavior towards staff, it is crucial to adhere to legal and institutional regulations. The nurse must obtain a physician's order for the restraints to ensure the approach is medically necessary and appropriate. In this case, the correct time frame for obtaining a physician's order after initiating restraints is within 1 hour (Option C). It's important for healthcare providers to regularly assess and document the patient's condition and need for continued restraint, ensuring patient safety and compliance with healthcare regulations.