Which vitamin is essential for proper blood coagulation?

Vitamin K is essential for proper blood coagulation because it plays a critical role in the synthesis of several key proteins known as clotting factors that are necessary for blood coagulation. These proteins, including prothrombin, require vitamin K for their synthesis in the liver. Without sufficient vitamin K, the body cannot effectively stop bleeding due to a lack of proper coagulation factors, leading to increased bleeding tendencies and complications such as hemorrhaging.

Vitamin A, while important for vision and immune function, does not have a direct role in the coagulation process. Vitamin C is vital for collagen synthesis and antioxidant protection but is not involved in blood coagulation. Vitamin D primarily regulates calcium and phosphate metabolism in the body and supports bone health but does not play a direct role in coagulation. Hence, vitamin K is the only vitamin among the choices that directly influences the clotting cascade and is crucial for maintaining hemostasis.