The correct answer is option 4 - Vitamin K. Vitamin K is an essential nutrient that plays a significant role in blood clotting. Blood clotting, also known as coagulation, is a process that prevents excessive bleeding when blood vessels are damaged. Vitamin K helps in the synthesis of certain proteins known as clotting factors that are responsible for the formation of blood clots.

Option 1 - Vitamin A is incorrect. Although Vitamin A is crucial for good vision, growth, and development, it does not directly have a role in blood clotting.

Option 2 - Vitamin B is incorrect. The B-vitamins are a group of vitamins that are involved in various metabolic processes, but they do not have a direct role in blood clotting.

Option 3 - Vitamin D is incorrect. Vitamin D is primarily involved in calcium absorption and bone health, and it does not directly contribute to blood clotting.

Alert - The correct answer should be option 4 - Vitamin K.