This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid, Subject name: Surgery
Which is the investigation of choice to differentiate between benign and malignant thyroid nodule? 
Select and explain. 
A. USG, B. FNAC, C. Scintigraphy, D. Biopsy
D: Biopsy
Answer: D: Biopsy 
Explanation: FNAC is investigation of choice to diagnose solitary thyroid nodule but it cannot differentiate follicular adenoma from follicular carcinoma Diagnosis of follicular carcinoma is based on vascular invasion/ capsular invasionthat can be seen on biopsy only and not on FNAC