**Core Concept**
Dietary fibre plays a crucial role in reducing atherosclerosis by modulating the gut microbiota and influencing lipid metabolism.

**Why the Correct Answer is Right**
The mechanism of action of dietary fibre in reducing atherosclerosis involves the formation of short-chain fatty acids (SCFAs) through fermentation by gut microbiota. SCFAs, particularly butyrate, propionate, and acetate, have been shown to:
* Inhibit the synthesis of cholesterol in the liver
* Increase the expression of LDL receptors on the liver cells, thereby enhancing the clearance of LDL cholesterol from the bloodstream
* Reduce the production of pro-inflammatory cytokines in the endothelium, which contributes to the development of atherosclerosis

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not specify a mechanism of action. While dietary fibre can reduce atherosclerosis, stating "it binds to bile acids" is an oversimplification and does not accurately describe the primary mechanism.

**Option B:** This option is incorrect as it mentions "increased excretion of cholesterol" but does not provide a clear mechanism. While dietary fibre can increase the excretion of bile acids, which in turn reduces the reabsorption of cholesterol, this is not the primary mechanism by which dietary fibre reduces atherosclerosis.

**Option C:** This option is incorrect as it mentions "inhibition of HMG-CoA reductase" but is not accurate. While HMG-CoA reductase inhibitors (statins) are a class of drugs that inhibit this enzyme, dietary fibre does not work through this mechanism to reduce atherosclerosis.

**Clinical Pearl / High-Yield Fact**
A high-fibre diet can reduce the risk of cardiovascular disease by up to 20% by modulating the gut microbiota and influencing lipid metabolism.

**Correct Answer:** C. Inhibition of HMG-CoA reductase is incorrect. The correct answer is not provided as the correct answer was not given in the prompt.