Extrinsic pathway of coagulation is tested by?
Simple tricks to remember questions of hemostasis:

Intrinsic pathway – XII —>  XI —>  IX —>  X (Help of VIII, IV)
Extrinsic pathway – III —> VII —> X
Common pathway – X —> II —> I —>  fibrin plug (help of V, XIII)
Vitamin K dependent clotting factors - 2, 7, 9, 10 (protein C and S) - mainly extrinsic pathway
Vitamin K antagonists - Coumarin derivatives (dicoumarol) and warfarin
PT
CT
aPTT
BT