Final answer:
The client's severe nasal congestion can be addressed by administering decongestant medication, elevating the head of the bed, and encouraging increased fluid intake.
Step-by-step explanation:
The client's severe nasal congestion can be addressed by administering decongestant medication (option a). Decongestants, such as phenylephrine, can help to clear the nasal passages by dilating the bronchioles in the lungs, allowing accumulated mucus to be cleared out. Elevating the head of the bed (option b) can also help to relieve nasal congestion by reducing blood flow to the area. Additionally, increasing fluid intake (option c) can help to counteract congestion by moisturizing the respiratory mucosa.