## Core Concept
The body's glucose regulation is primarily managed through the action of insulin and glucagon. After a meal, blood glucose levels rise due to the digestion and absorption of carbohydrates. In response, the pancreas releases insulin, which facilitates the uptake of glucose by cells.

## Why the Correct Answer is Right
The normal range for arterial blood glucose concentration in humans after a meal is generally considered to be **less than 140 mg/dL** but can slightly vary based on the specific criteria used. The body maintains blood glucose levels within a narrow range through tight regulatory mechanisms. After a meal, especially one with a high glycemic index, blood glucose can rise but is typically kept below 140 mg/dL in healthy individuals due to insulin's action.

## Why Each Wrong Option is Incorrect
* **Option A:** 300 mg/dL - This range is significantly elevated and would be considered hyperglycemic, indicative of uncontrolled diabetes mellitus.

## Clinical Pearl / High-Yield Fact
A key point to remember is the **oral glucose tolerance test (OGTT)** criteria, which defines normal glucose tolerance as a 2-hour post-glucose load value of < 140 mg/dL. For diabetes diagnosis, a value of 200 mg/dL or higher is used. The American Diabetes Association (ADA) also provides criteria for impaired glucose tolerance (fasting < 126 mg/dL and 2-hour value of 140-199 mg/dL). **Correct Answer: C. < 140 mg/dL.**