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
In which of the following conditions sialography is contraindicated: 
Select and explain. 
A. Ductal calculus, B. Chronic parotitis, C. Parotid obstruction, D. Acute sialadenitis
D: Acute sialadenitis
Answer: D: Acute sialadenitis 
Explanation: Main Indications of Sialography Salivary duct stones Stricture Fistula. penetrating injury Intraglandular and sometimes extra glandular mass lesions. Contraindications Iodine allergy Acute sialadenitis Contrast Water soluble media (Meglumine diatrizoate)