**Core Concept**
Chemotaxis refers to the movement of cells in response to chemical stimuli, which is a critical process in various physiological and pathological conditions, such as inflammation and immune responses. This phenomenon involves the interaction between chemokines (or other chemical signals) and their specific receptors on the surface of cells.

**Why the Correct Answer is Right**
Chemotaxis is mediated by G-protein coupled receptors (GPCRs) that are activated by binding to chemokines. This activation triggers a signaling cascade that ultimately leads to changes in the cytoskeleton of the cell, resulting in its movement towards the source of the chemical stimulus. The process of chemotaxis is essential for the recruitment of immune cells, such as neutrophils and macrophages, to sites of infection or inflammation.

**Why Each Wrong Option is Incorrect**
**Option A:** Chemotaxis is not the same as chemiluminescence, which is the process by which light is emitted as a result of a chemical reaction.
**Option B:** Chemotaxis is not the movement of cells in response to mechanical stimuli, which is known as mechanotaxis.
**Option C:** Chemotaxis is not the same as chemokinesis, which is the increase or decrease in the speed of cell movement in response to chemical stimuli.

**Clinical Pearl / High-Yield Fact**
Chemotaxis plays a crucial role in the pathogenesis of various diseases, including atherosclerosis, rheumatoid arthritis, and cancer metastasis. Understanding the mechanisms of chemotaxis is essential for the development of novel therapeutic strategies for these conditions.

**Correct Answer: C. Movement of cells in response to chemical stimuli.**