This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid Gland, Subject name: Surgery
Investigation of choice in discrete thyroid swellings 
Select and explain. 
A. USG, B. FNAC, C. Biopsy, D. RAI
B: FNAC
Answer: B: FNAC 
Explanation: Ans. (b) FNACRef: Bailey and Love page 751/26th edition* Fine-needle aspiration cytology is the investigation of choice in discrete thyroid swellings* A discrete swelling in an otherwise impalpable gland is termed isolated or solitary, whereas the preferred term is dominant for a similar swelling in a gland with clinical evidence of generalised abnormality in the form of a palpable contralateral lobe or generalised mild nodularity.* About 70 per cent of discrete thyroid swellings are clinically isolated and about 30 per cent are dominant