The correct answer is option 3, Vitamin-K. Vitamin-K plays a crucial role in blood coagulation, which is the process of clot formation to prevent excessive bleeding. This vitamin helps in the production of several clotting factors in the body, including prothrombin and fibrinogen. These clotting factors are essential for forming a stable blood clot when there is an injury or damage to blood vessels. Vitamin-K deficiency can lead to prolonged bleeding and increased risk of excessive bleeding. It is found in green leafy vegetables, broccoli, Brussels sprouts, and certain vegetable oils. Although option 1, Vitamin-A, is essential for vision and maintaining healthy skin, it is not directly involved in blood coagulation. Options 2 and 4, Vitamin-C and Vitamin-E, respectively, have other important functions in the body but are not directly involved in blood coagulation.