**Core Concept**
The question is testing the concept of carbohydrate absorption and the role of gastrointestinal enzymes in this process. The underlying principle is that certain drugs can inhibit the activity of enzymes responsible for carbohydrate digestion, thereby delaying absorption.

**Why the Correct Answer is Right**
The correct answer is an alpha-glucosidase inhibitor, which works by inhibiting the activity of enzymes such as sucrase, maltase, and lactase in the small intestine. These enzymes break down carbohydrates into simple sugars, which are then absorbed into the bloodstream. By inhibiting these enzymes, alpha-glucosidase inhibitors delay the absorption of dietary carbohydrates, thereby reducing the peak postprandial glucose levels. This class of drugs is commonly used in the management of type 2 diabetes.

**Why Each Wrong Option is Incorrect**
**Option A:** is incorrect because it is a biguanide, a class of oral antidiabetic drugs that primarily work by decreasing glucose production in the liver. While biguanides do have some effect on carbohydrate absorption, they are not taken during meals to delay absorption.
**Option B:** is incorrect because it is a sulfonylurea, a class of oral antidiabetic drugs that work by stimulating insulin release from the pancreas. Sulfonylureas do not affect carbohydrate absorption and are not taken during meals.
**Option C:** is incorrect because it is a thiazolidinedione, a class of oral antidiabetic drugs that work by improving insulin sensitivity. Thiazolidinediones do not affect carbohydrate absorption and are not taken during meals.

**Clinical Pearl / High-Yield Fact**
Alpha-glucosidase inhibitors should be taken at the beginning of meals to effectively delay carbohydrate absorption. It is essential to note that these drugs do not affect the digestion of fats and proteins.

**Correct Answer:** C. Acarbose.