Which of the following can be a reason for nail discoloration?

Nail discoloration can occur for various reasons, and one significant cause is injury or trauma to the nail. When a nail suffers an impact, it can lead to bleeding beneath the nail, commonly referred to as a subungual hematoma. This bleeding can cause the nail to develop a dark coloration, often appearing red, purple, or black, depending on the severity of the injury and the amount of blood trapped beneath the nail. Over time, as the nail grows out and the old nail is replaced, the discoloration may gradually move away from the cuticle area. This is a direct result of physical damage and is a common observation in nail care.

While other factors mentioned may influence the nail's appearance, they do not typically lead to discoloration in the same direct manner. For instance, exposure to sunlight can affect the skin and may alter the appearance of nails, but it is not a primary factor in causing discoloration. Similarly, vitamins in the diet can influence overall nail health but do not directly cause discoloration in the absence of other influencing factors. Regular soaking in water can lead to some temporary changes in the nails, but it isn’t normally the cause of significant long-term discoloration. Thus, the trauma to the nail stands out