**Core Concept**
Programmed cell death, also known as apoptosis, is a form of cell death that occurs in multicellular organisms. It's an essential process for eliminating damaged or unwanted cells, maintaining tissue homeostasis, and preventing cancer. Apoptosis is characterized by a series of morphological changes, including cell shrinkage, chromatin condensation, and DNA fragmentation.

**Why the Correct Answer is Right**
Apoptosis is mediated by a family of cysteine proteases called caspases, which are activated by various intracellular and extracellular signals. These signals can be triggered by DNA damage, viral infection, or other forms of cellular stress. The activation of caspases leads to the cleavage of key cellular proteins, resulting in the characteristic morphological changes of apoptosis. For example, caspase-3 is a key executioner caspase involved in the final stages of apoptosis.

**Why Each Wrong Option is Incorrect**
**Option A:** Necrosis is a form of cell death that occurs due to external factors, such as infection or toxin exposure. It's not a programmed process like apoptosis.
**Option B:** Autophagy is a process of cellular self-digestion, where cells recycle their own components to maintain homeostasis. While it's related to cell survival, it's not a form of programmed cell death.
**Option C:** Mitosis is the process of cell division, where a cell divides into two daughter cells. It's not a form of cell death.

**Clinical Pearl / High-Yield Fact**
Apoptosis plays a crucial role in various diseases, including cancer, where it can act as a tumor suppressor. The loss of apoptotic function can contribute to cancer development and progression.

**Correct Answer:** C.