**Core Concept**
The most accepted theory of atherosclerosis is a multifactorial process involving inflammation, lipid deposition, and vascular remodeling. This complex interplay leads to the development of atherosclerotic plaques, which can cause cardiovascular disease. The process involves various cell types, including endothelial cells, smooth muscle cells, and immune cells.

**Why the Correct Answer is Right**
The correct answer is the "response-to-injury" theory, also known as the "injury-repair" theory. This theory proposes that atherosclerosis is initiated by an injury to the endothelial layer of the arterial wall, which triggers an inflammatory response and the subsequent accumulation of lipids, smooth muscle cells, and extracellular matrix. The injured endothelial cells release various growth factors and cytokines, which attract immune cells and promote the proliferation of smooth muscle cells. This process leads to the formation of atherosclerotic plaques.

**Why Each Wrong Option is Incorrect**
**Option A:** The "lipid-only" theory is an oversimplification of the atherosclerotic process, as it does not account for the role of inflammation and endothelial injury.
**Option B:** The "infectious" theory is not supported by current evidence, as atherosclerosis is not primarily caused by an infectious agent.
**Option C:** The "genetic-only" theory is incorrect, as atherosclerosis is a multifactorial disease influenced by both genetic and environmental factors.

**Clinical Pearl / High-Yield Fact**
Atherosclerosis is a chronic, progressive disease that can be prevented or slowed with lifestyle modifications, including smoking cessation, regular exercise, and a healthy diet.

**Correct Answer: C. Response-to-injury theory.**