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-30-year old male is having Attic cholesteatoma of left ear with lateral sinus thromboplebitis. Which of the following will be the operation of choice - 
Select and explain. 
A. Intact canal will be the operation of choice, B. Simple mastoidectomy with tympanoplasty, C. Canal wall down mastoidectomy, D. Mastoididectomy with cavity obliteration
C: Canal wall down mastoidectomy
Answer: C: Canal wall down mastoidectomy 
Explanation: None