This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Radiology
Which of the following type of Hydatid cyst denotes a complicated cyst? 
Select and explain. 
A. Type I, B. Type II, C. Type III, D. Type IV
D: Type IV
Answer: D: Type IV 
Explanation: Ans DType IV hydatid cyst are complicated. They can be due to Internal cyst rupture or external. It is probably related to decreasing intracystic pressure, degeneration, host response, trauma or response to medical therapy and percutaneous drainage. Internal rupture causes death of the parasite.