This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Women Imaging, Subject name: Radiology
Investigation to differentiate between a scar tissue and residual/recurrence of a breast tumor is 
Select and explain. 
A. USG, B. Mammography, C. MRI, D. All of the above
C: MRI
Answer: C: MRI 
Explanation: Ix for differentiating scar Vs residual / recurrence of Ca Breast- CE-MRI Breast scar Post-surgical breast scar is a benign complication that usually occurs following surgical intervention to breast tissue. It can, however, be a strong and potentially very confusing mimicker of breast malignancy. Residual breast tumor It is a remaining poion of the original primary breast cancer after incomplete resection or following radiotherapy or chemotherapy. Residual Breast Tumor shows contrast enhancement but scars donot enhance on a Contrast Enhanced Mri