**Core Concept**
Abetalipoproteinemia, also known as Bassen-Kornzweig syndrome, is a rare inherited disorder characterized by impaired absorption of dietary fats and fat-soluble vitamins. It is caused by a deficiency in a specific protein involved in the assembly and secretion of very-low-density lipoproteins (VLDL) from the liver.

**Why the Correct Answer is Right**
The correct answer is due to a deficiency in the microsomal triglyceride transfer protein (MTTP). MTTP is essential for the assembly and secretion of VLDL from the liver, which is then transported to peripheral tissues for the distribution of endogenous triglycerides and other lipids. Without functional MTTP, VLDL assembly is impaired, leading to reduced levels of apolipoproteins B-48 and B-100 in the plasma. This results in the characteristic features of abetalipoproteinemia, including impaired lipid absorption and fat-soluble vitamin deficiencies.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the disease is not caused by a deficiency in chylomicron remnants, but rather by a defect in VLDL assembly.

**Option B:** This option is incorrect because the disease is not caused by a deficiency in apolipoprotein A-I, which is primarily involved in the assembly of high-density lipoproteins (HDL).

**Option C:** This option is incorrect because the disease is not caused by a deficiency in lipoprotein lipase, which is primarily involved in the hydrolysis of triglycerides in chylomicrons and VLDL.

**Clinical Pearl / High-Yield Fact**
Abetalipoproteinemia is a rare but important disorder to recognize, as it highlights the importance of the microsomal triglyceride transfer protein in lipid metabolism. The disease can be diagnosed through a combination of clinical presentation, laboratory tests, and genetic analysis.

**Correct Answer:** D. Microsomal triglyceride transfer protein (MTTP) deficiency.