**Core Concept**
Fructose uptake in the small intestine is facilitated by a specific transport mechanism. The primary method involves **facilitated diffusion**, a process that does not require energy. This process is crucial for the absorption of fructose, a simple sugar commonly found in fruits and many processed foods.

**Why the Correct Answer is Right**
The correct mechanism for fructose uptake is via **facilitated diffusion** by a specific transporter known as **GLUT5 (Glucose Transporter Type 5)**. This transporter is located on the apical surface of the enterocytes in the small intestine and facilitates the uptake of fructose from the intestinal lumen into the enterocytes.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not specify the correct transporter or mechanism for fructose uptake.
**Option B:** Incorrect as it is not the primary method for fructose absorption in the small intestine.
**Option C:** Incorrect because, although it is involved in sugar transport, it is not specific for fructose.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that **GLUT5** plays a critical role in fructose absorption, and its dysfunction can lead to issues with fructose metabolism.

**Correct Answer:** D. GLUT5.