What is the main component of plasma that plays a key role in blood clotting?

Fibrinogen is the main component of plasma that plays a crucial role in blood clotting. It is a soluble plasma protein produced by the liver and is essential for hemostasis, the process that prevents and stops bleeding. During the clotting process, fibrinogen is converted into fibrin strands by the enzyme thrombin. These strands weave through the platelet plug formed at the site of injury, effectively stabilizing the clot and allowing the healing process to begin.

The other components listed, such as red blood cells, white blood cells, and globulins, have important functions within the blood but are not directly involved in the clotting process. Red blood cells are primarily responsible for transporting oxygen. White blood cells are integral to the immune response, helping fight infections. Globulins serve various functions including transport and immune responses but do not play a direct role in the formation of blood clots. Thus, fibrinogen's specific function in clot formation makes it the correct choice in this context.