This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Diameter of varicose veins is 
Select and explain. 
A. ≥ 1mm, B. ≥ 2mm, C. ≥ 4mm, D. ≥ 3mm
D: ≥ 3mm
Answer: D: ≥ 3mm 
Explanation: Varicose veins are dilated tortuous subcutaneous veins ≥ 3mm in diameter.