The right answer is by the sticking of platelets to other platelets.
The platelets attach to the injured walls of the endothelium via the von Willebrand factor. Once fixed, the platelets will be activated and conformational change to attract more platelets to the injured site so as to form a white clot. Then the coagulation factor will intervene including the factor XII which is activated in contact with the negatively charged platelet membrane, and will activate the rest of the coagulation factors.
Proposals 1 and 3 trigger primary hemostasis and not coagulation.
Proposition 4 concerns the exogenous pathway of activation of coagulation.
