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: Medicine
A 35 year old Lady Malti has unilateral headache, nausea, vomiting and visual blurring. The diagnosis is 
Select and explain. 
A. Cluster headache, B. Glaucoma, C. Subarachnoid haemorrhage, D. Posterior fossa cyst.
B: Glaucoma
Answer: B: Glaucoma 
Explanation: Answer is B (Glaucoma): Presence of visual blurring and female sex suggest a diagnosis of glaucoma over cluster headache amongst the options provided. Differential diagnosis are : Female patient (Glaucoma is about four times more common in females while 80% of patients with cluster headache are males) Visual blurring (Visual blurring is a feature of Glaucoma. Cluster headache has ocular features mainly limited to reddening of eye and homolateral lacrimation but vision has not been mentioned as being affected).