**Core Concept**
Protein A of Staphylococcus aureus is a cell wall component that plays a crucial role in the pathogenesis of the bacterium. It is a surface protein that binds to the Fc region of immunoglobulins, specifically IgG.

**Why the Correct Answer is Right**
Protein A binds to the Fc region of IgG through a specific interaction between the protein's B-domain and the Fc region's CH2 domain. This binding is a non-covalent, high-affinity interaction that allows Protein A to inhibit opsonization and phagocytosis of Staphylococcus aureus by neutrophils and macrophages. The binding of Protein A to IgG also prevents the activation of the complement system, thereby facilitating the bacterium's evasion of the host immune response.

**Why Each Wrong Option is Incorrect**
* **Option A:** Incorrect, as Protein A does not bind to IgM.
* **Option B:** Incorrect, as Protein A does not bind to IgA.
* **Option C:** Incorrect, as Protein A does not bind to IgE.

**Clinical Pearl / High-Yield Fact**
It is essential to recognize that Protein A can interfere with the laboratory diagnosis of infections caused by Staphylococcus aureus, as it can bind to antibodies used in diagnostic tests, leading to false-negative results.

**Correct Answer:** D.