Correct Answer: Heparin

Solution : The correct option is Heparin.

Because to the presence of anticoagulants such as heparin and endothelial cells lining the blood vessels, blood fails to clot while travelling through the blood vessels. These natural processes prevent blood from clotting spontaneously inside the circulation, ensuring that blood remains liquid as it passes through the blood arteries. Blood clotting is the outcome of a complicated series of chemical processes that culminate in the creation of a blood clot. This process is dependent on blood clotting proteins, enzymes, and molecules such as fibrinogen, thrombin, platelets, and calcium ions, among others.