The correct answer for the deficiency that leads to bleeding gums, falling of teeth, fragile bones, and delayed wound healing is Vitamin C.

Vitamin C, also known as ascorbic acid, is an essential vitamin that plays a crucial role in various bodily functions. It is a powerful antioxidant that helps protect cells from damage and supports the immune system.

The deficiency of Vitamin C can result in a condition called scurvy, which is characterized by symptoms such as bleeding gums, loose teeth, and delayed wound healing. Vitamin C is essential for the synthesis of collagen, a protein that helps maintain the structure of blood vessels, gums, and bones. When there is a deficiency of Vitamin C, collagen production is disrupted, leading to weakened blood vessels and gums, resulting in bleeding, loosening of teeth, and poorer wound healing.

It is important to note that while other vitamins like Vitamin K, Vitamin D, and Vitamin B also play essential roles in the body, they are not specifically associated with the aforementioned symptoms. Thus, the correct answer is option 1, Vitamin C.