**Core Concept**
The question is testing the student's knowledge of new antidiabetic drugs, specifically those effective in postprandial glucose control. Postprandial glucose control refers to the ability of a drug to manage blood glucose levels after a meal, which is crucial in preventing hyperglycemia and its associated complications in diabetes mellitus.

**Why the Correct Answer is Right**
The correct answer is SGLT-2 inhibitors, such as dapagliflozin or empagliflozin. These drugs work by inhibiting the sodium-glucose cotransporter 2 (SGLT2) in the proximal convoluted tubule of the kidneys, reducing glucose reabsorption and increasing urinary glucose excretion. This mechanism of action leads to a decrease in postprandial glucose levels, as well as weight loss and improved cardiovascular outcomes.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify the mechanism of action or the class of drugs effective in postprandial glucose control. While metformin is a first-line antidiabetic drug, it is not specifically effective in postprandial glucose control.
* **Option B:** This option is incorrect because GLP-1 receptor agonists, such as exenatide or liraglutide, primarily work by enhancing glucose-dependent insulin secretion and suppressing glucagon secretion, but they do not specifically target postprandial glucose control.
* **Option C:** This option is incorrect because DPP-4 inhibitors, such as sitagliptin or saxagliptin, primarily work by inhibiting dipeptidyl peptidase-4 (DPP-4) and increasing GLP-1 levels, but they do not specifically target postprandial glucose control.

**Clinical Pearl / High-Yield Fact**
SGLT-2 inhibitors are effective in postprandial glucose control due to their ability to reduce glucose reabsorption in the kidneys, leading to improved glycemic control and weight loss. This class of drugs has also been shown to have cardiovascular benefits, making them an important addition to the treatment armamentarium for type 2 diabetes mellitus.

**Correct Answer: C. Dapagliflozin.**