**Core Concept**
Apoptosis, or programmed cell death, is a vital process for maintaining tissue homeostasis and preventing cancer. The **Bcl-2 family** of proteins plays a crucial role in regulating apoptosis.

**Why the Correct Answer is Right**
The correct answer is related to the **Bcl-2** protein, which is known to inhibit apoptosis by preventing the release of cytochrome c from the mitochondria, thereby blocking the activation of **caspases**. This anti-apoptotic effect is crucial for cell survival.

**Why Each Wrong Option is Incorrect**
**Option A:** Is incorrect because it does not relate to the inhibition of apoptosis.
**Option B:** Does not accurately describe an inhibitor of apoptosis.
**Option C:** Is also incorrect as it is not directly involved in inhibiting apoptosis.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that **overexpression of Bcl-2** can lead to cancer, as it allows damaged cells to survive and proliferate.

**Correct Answer:** D. Bcl-2