Which response is appropriate when a patient complains of worsening nasal congestion despite the use of oxymetazoline nasal spray every 2 hours?
a) "You should continue using the nasal spray as directed."
b) "You may need to consult your healthcare provider for further evaluation."
c) "Try using the nasal spray more frequently, every hour."
d) "Stop using the nasal spray immediately and switch to a different brand."