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: Skin
A 60- year - old patient presented with several bullous lesions for the last 3 days; each bulla was surrounded by an erythematous halo. There were multiple target lesions. Patient also had oral erosions. The most likely diagnosis is: 
Select and explain. 
A. Chicken pox, B. Herpes simplex, C. Herpes zoster, D. Steven- Johnson syndrome
D: Steven- Johnson syndrome
Answer: D: Steven- Johnson syndrome 
Explanation: D. i.e. Steven Johnson syndrome