**Core Concept**
The mechanism of action of bevacizumab is related to its role as a **monoclonal antibody** targeting **vascular endothelial growth factor (VEGF)**. Bevacizumab is used in the treatment of various cancers, including colorectal, lung, and breast cancer. It works by inhibiting **angiogenesis**, the process of new blood vessel formation.

**Why the Correct Answer is Right**
Bevacizumab binds to **VEGF**, preventing its interaction with **VEGF receptors** on the surface of endothelial cells. This inhibits the signaling pathway that promotes **angiogenesis**, thereby reducing the growth of new blood vessels that supply nutrients to tumors. By inhibiting tumor angiogenesis, bevacizumab exerts its anti-tumor effect.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because bevacizumab does not directly target tumor cells.
**Option B:** Incorrect as it is not related to the mechanism of action of bevacizumab.
**Option C:** Incorrect because it is unrelated to the function of bevacizumab.
**Option D:** Incorrect as the description does not match the mechanism of action of bevacizumab.

**Clinical Pearl / High-Yield Fact**
Bevacizumab's mechanism highlights the importance of **angiogenesis** in tumor growth and the potential of targeting **VEGF** pathways in cancer therapy. Remember that bevacizumab is a **monoclonal antibody** and its use can be associated with specific side effects due to its mechanism of action.

**Correct Answer:** D. Bevacizumab is a monoclonal antibody that binds to VEGF.