**Core Concept**
Torcetrapib is a cholesteryl ester transfer protein (CETP) inhibitor, which plays a crucial role in lipid metabolism. CETP is involved in the transfer of cholesteryl esters from high-density lipoprotein (HDL) to low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL) in exchange for triglycerides.

**Why the Correct Answer is Right**
Torcetrapib works by inhibiting CETP, thereby preventing the transfer of cholesteryl esters from HDL to LDL and VLDL. This leads to an increase in HDL cholesterol levels and a decrease in LDL and VLDL cholesterol levels, resulting in a hypolipidemic effect. The inhibition of CETP also leads to an increase in apolipoprotein A-I (apoA-I), the main protein component of HDL.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not accurately describe the mechanism of action of torcetrapib. While statins do inhibit HMG-CoA reductase, they do not inhibit CETP.
* **Option B:** This option is incorrect because it mentions the mechanism of action of niacin, which is a different class of lipid-lowering agents.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that CETP inhibitors, like torcetrapib, can have a paradoxical effect on HDL levels, leading to increased cardiovascular risk. This is a critical concept to understand in lipid management.

**Correct Answer: C. Inhibiting CETP. By preventing the transfer of cholesteryl esters from HDL to LDL and VLDL.**