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: ENT
A 12 year old presents with fever, unilateral post auricular pain, mastoid bulging displacing the pinna forward and outwards with loss of bony trabeculae. This patient has history of chronic persistent pus discharge from same ear. Treatment of choice is? 
Select and explain. 
A. Antibiotics only, B. Incision and drainage, C. Antibiotics, incision and drainage, D. Mastoidectomy with incision, drainage and antibiotics
D: Mastoidectomy with incision, drainage and antibiotics
Answer: D: Mastoidectomy with incision, drainage and antibiotics 
Explanation: The patient is presenting with features of postauricular subperiosteal abscess. Treatment for this is antibiotics along with drainage of abscess and coical mastoidectomy.This patient has developed this abscess as a complication of CSOM (History of chronic ear discharge) for which he requires meastoidectomy.