**Core Concept**
The human plasma lipoproteins are a group of lipids and proteins that play a crucial role in lipid metabolism and transport. The main types of lipoproteins are chylomicrons, very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL). Each type of lipoprotein has a distinct composition and function.

**Why the Correct Answer is Right**
The chylomicrons are the largest and most buoyant lipoproteins, primarily responsible for transporting dietary triglycerides from the intestines to the liver and peripheral tissues. They contain a high percentage of triacylglycerol (up to 90%) and are rich in apolipoproteins B-48 and A-I. The high triacylglycerol content of chylomicrons is due to their role in transporting dietary lipids, which are primarily in the form of triacylglycerol.

**Why Each Wrong Option is Incorrect**
**Option A:** VLDL is incorrect because, although it also contains triacylglycerol, its percentage is significantly lower than that of chylomicrons.
**Option B:** LDL is incorrect because it is primarily composed of cholesterol and cholesterol esters.
**Option C:** HDL is incorrect because it is rich in phospholipids, unesterified cholesterol, and apolipoproteins, but contains a low percentage of triacylglycerol.

**Clinical Pearl / High-Yield Fact**
Chylomicrons are the primary lipoproteins involved in the transport of dietary lipids and are often elevated in conditions such as hypertriglyceridemia, pancreatitis, and atherosclerosis.

**Correct Answer: A. Chylomicrons**