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
Malignant otitis externa is characterized by-a) Caused by pseudomonas aeruginosab) Malignancy of external auditory canalc) Granulation tissue is seen in the floor of external auditory canald) Radiotherapy can be givene) Gallium scan helpful for monitoring treatment 
Select and explain. 
A. acd, B. bde, C. ace, D. ade
C: ace
Answer: C: ace 
Explanation: None