**Core Concept**
Bacterial adhesion is the initial step in the pathogenesis of many bacterial infections, where bacteria attach to the host cell surface or epithelial lining. This process involves various molecules and structures on both the bacterial and host cells. The adhesion of bacteria to the host cells is mediated by specific interactions between bacterial adhesins and host cell receptors.

**Why the Correct Answer is Right**
Bacterial adhesins are proteins or glycoproteins on the surface of bacteria that facilitate their attachment to host cells. These adhesins bind to specific receptors on the host cell surface, such as lectins, integrins, or other adhesion molecules. The most common adhesins involved in bacterial adhesion include pili, fimbriae, and invasins. For example, type 1 pili in E. coli bind to D-mannose residues on the host cell surface, while fimbriae in Streptococcus pyogenes bind to hyaluronic acid on the host cell surface.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not mention any specific molecules or structures involved in bacterial adhesion.
**Option B:** This option is incorrect because it is a general term and does not specify the type of molecule or structure involved in bacterial adhesion.
**Option C:** This option is incorrect because it refers to the process of bacterial invasion, which is a separate step in the pathogenesis of bacterial infections.

**Clinical Pearl / High-Yield Fact**
It is essential to recognize that bacterial adhesion is a critical step in the development of many bacterial infections, including urinary tract infections (UTIs), respiratory tract infections, and gastrointestinal infections. Understanding the mechanisms of bacterial adhesion can help in the development of targeted therapeutic strategies to prevent or treat these infections.

**Correct Answer:** C.