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
Which is not used in treatment of superficial venous thrombosis -a) Immediate anticoagulationb) Rest and elevationc) Analgesicsd) Treat assosiated malignancy 
Select and explain. 
A. ac, B. ab, C. ad, D. bc
B: ab
Answer: B: ab 
Explanation: 1) Patient should not be kept at bed rest 2) Anti coagulation therapy is used when thrombus extends proximally to within 1 cm of the saphenofemoral junction to prevent the extension into femoral vein.