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: Radiology
Which of the following is not a CT feature ofAdrenal adenoma – 
Select and explain. 
A. Low attenuation, B. Homogenous density and well defined borders, C. Enhances rapidly, contrast stays in it for a relatively longer time and washes out late, D. Calcification is rare
C: Enhances rapidly, contrast stays in it for a relatively longer time and washes out late
Answer: C: Enhances rapidly, contrast stays in it for a relatively longer time and washes out late 
Explanation: Adrenal adenoma on contrast-enhanced CT/MRI shows rapid uptake and relatively rapid washout of contrast material than do non adenomasQ.
Adenoma: CT features

Well defined/sharply defined 
<5 cm in size
Low attenuation (<10 HU) due to lipid content
Mild homogenous enhancement
Relatively rapid washout of contrast material (due to lack of large interstitial spaces
Relatively rapid washout is characteristic of adenoma