This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
An attack of cluster headache can be aborted by 
Select and explain. 
A. Morphine administration, B. Breathing oxygen, C. Aspirin administration, D. Sublingual nitroglycerine administration
B: Breathing oxygen
Answer: B: Breathing oxygen 
Explanation: Cluster headache is unilateral and among the most painful of all headache disorders. Periorbital pain is commonly associated with autonomic symptoms including homoLateral lacrimation. Abortive medicines including the use of 100% oxygen at the outset of an episode, are often useful in confirming diagnosis. Oxygen inhalation results in rapid resolution of symptoms over 70% cases.
Triptan therapy, short courses of glucocorticoids are also effective.