Ans. is 'a' i.e., FNAC In any patient with a breast lump or other symptoms suggestive of carcinoma, diagnosis should be made by a combination of : 'Triple Assessment' : a. Clinical assessment b. Radiological imaging c. Tissue sampling for either cytological or histological examination. FNAC is more than often the first investigation for a tissue assessment. Bailey writes ? "FNAC is the least invasive technique for obtaining a cell diagnosis and is very accurate if both operator and cytologists are experienced. However false negatives do occur, mainly through sampling error, and invasive cancer cannot be distinguished from 'in situ' disease. A histological specimen taken by core biopsy allows a definitive preoperative diagnosis, differentiates between duct carcinoma in situ (DCIS) and invasive disease and also allows the tumor to be stained for receptor status. This is impoant before commencing neoadjuvant therapy."