A 23 year old woman presents with a 1 cm small smooth, firm, mobile mass in her left breast. She is very anxious. What is the most appropriate investigation?

The key is B. US breast. [This is fibroadenoma of the breast (breast mouse) for which US of breast is the appropriate investigation and if it reveal a fibrous lump we shall go for FNAC. Another point a doctor should know that for any suspicious breast lesion radiology should must be done before options of biopsy and investigation of choice in radiology is US scan before the age of 35 and mammography after the age of 35. In that term also for this case the investigation of choice is US breast].