Final answer:
A nonpharmacological intervention that the nurse can implement for a patient experiencing a headache and awaiting pain medication is to softly play relaxing music.
Step-by-step explanation:
When a patient arrives at the emergency department experiencing a headache and rates the pain as 7 on a 0 to 10 pain scale, a nonpharmacological intervention that the nurse can implement while awaiting orders for pain medication is to softly play music that the patient finds relaxing (option C). Playing relaxing music can help distract the patient from the pain and promote a sense of calm and relaxation.