## **Core Concept**
The Epstein-Barr Virus (EBV) is a type of herpesvirus that primarily infects B-cells. The entry of EBV into B-cells is a critical step in its lifecycle. This process involves specific receptors on the surface of B-cells.

## **Why the Correct Answer is Right**
The correct answer, , refers to the complement receptor 2, also known as CD21. EBV uses its envelope glycoprotein gp350 to bind to CD21 (CR2) on the surface of B-cells. This binding is the initial step that facilitates the fusion of the viral envelope with the host cell membrane, allowing the virus to enter the B-cell. CD21 is a key receptor for EBV attachment and entry.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not accurately represent the receptor used by EBV to enter B-cells.
- **Option B:** This option is incorrect as it does not correspond to the known receptor for EBV entry into B-cells.
- **Option C:** This option might seem plausible but is incorrect because it does not specifically denote CD21 or CR2, which are crucial for EBV entry.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that EBV's ability to infect B-cells via CD21 (CR2) is fundamental to its pathogenesis, including its role in infectious mononucleosis (glandular fever) and its association with certain malignancies like Burkitt's lymphoma.

## **Correct Answer:** . CD21 (CR2)