**Core Concept**
Secondary hemorrhage, also known as delayed hemorrhage, refers to bleeding that occurs after the initial 24 hours following a surgical procedure or trauma. This type of hemorrhage is often caused by factors that become apparent after the initial stabilization of the patient.

**Why the Correct Answer is Right**
Secondary hemorrhage is typically seen in the setting of infection, which can cause the breakdown of blood clots and the erosion of blood vessels. This can lead to the re-bleeding of previously controlled hemorrhages. The most common cause of secondary hemorrhage is infection, often due to inadequate wound care, contamination, or the presence of a foreign body.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is not provided.
**Option C:** This option is not provided.
**Option D:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
It is essential to maintain meticulous wound care and monitor for signs of infection to prevent secondary hemorrhage. A high index of suspicion for infection and prompt treatment can significantly reduce the risk of this complication.

**Correct Answer: D. Infection**