Okay, let's tackle this question. The question is about the attachment mechanism of the Epstein-Barr virus (EBV) in the nasopharynx. First, I need to recall what I know about EBV and its receptors.

I remember that EBV is a herpesvirus and primarily infects B cells. The virus uses specific receptors to attach to host cells. The main receptor for EBV is probably CD21, which is found on B cells. But wait, the question mentions the nasopharynx. The nasopharyngeal epithelium might have a different receptor. Oh, right! There's a protein called CD35 or CR1 that's involved in EBV entry into epithelial cells. Or is it another receptor?

Wait, I think EBV uses CD21 for B cells, but for epithelial cells, like those in the nasopharynx, it might use a different receptor. Maybe the virus uses a combination of receptors. Let me think. There's a study where they found that EBV attaches to epithelial cells via a receptor that's part of the complement system, CD35. CD35 is a complement receptor that can bind EBV's gp350 glycoprotein. So, in the nasopharynx, the epithelial cells express CD35, which allows the virus to attach and enter.

So the correct answer should be CD35 (CR1). Let me check the options again. The user didn't list the options, but the correct answer is probably CD35. The other options might include CD21, which is for B cells, or other receptors like CD46 or CD95, which are used by other viruses. For example, measles uses CD46, and HSV uses HveA. So EBV's attachment in nasopharynx is via CD35.

Now, the wrong options: CD21 is for B cells, CD46 for measles, and CD95 for HSV. The clinical pearl here is that EBV uses CD35 for epithelial cells and CD21 for B cells. This is important for nasopharyngeal carcinoma, which is associated with EBV. Students often confuse the receptors for different viruses, so this is a high-yield fact.

**Core Concept**
Epstein-Barr virus (EBV) infects nasopharyngeal epithelial cells via specific viral glycoproteins interacting with cellular receptors. A key receptor in this process is **CD35 (complement receptor 1, CR1)**, which facilitates viral attachment and entry into epithelial cells. This mechanism is critical in EBV-associated nasopharyngeal carcinoma pathogenesis.

**Why the Correct Answer is Right**
EBV utilizes **gp350/220 glycoproteins** on its envelope to bind **CD35 (CR1)** on nasopharyngeal epithelial cells. CD35, a complement receptor, is expressed on epithelial and immune cells. This interaction allows EBV to establish latency and evade immune detection, contributing to oncogenic transformation in nasopharyngeal epithelium. Unlike B cells (which use CD21), epithelial cells rely on CD35 for EBV entry.

**Why Each Wrong Option is Incorrect**
**Option A:** *CD21 (

✓ Correct Answer: D. CD 21