This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
Lactating women with painful breast, 1st investigation to be done should be NOT RELATED-SURGERY 
Select and explain. 
A. USG, B. Mammography, C. CT, D. MRI
A: USG
Answer: A: USG 
Explanation: .