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: Medicine
The feature of benign nature of solitary pulnonary nodule –  a) 6cm size  b) Acute onset   c) Small speckts of calcification  d) Popcorn calcification 
Select and explain. 
A. ab, B. bd, C. cd, D. abd
C: cd
Answer: C: cd 
Explanation: None