**Core Concept**
The Proximal Convoluted Tubule (PCT) is a crucial part of the nephron, responsible for reabsorbing glucose, amino acids, and other essential nutrients back into the bloodstream. The PCT is lined with a specialized epithelium that enables these reabsorption processes.

**Why the Correct Answer is Right**
The epithelium present in the PCT is characterized by **microvilli** on the apical surface, which increase the surface area for reabsorption. The cells of the PCT also contain **brush border enzymes**, such as alpha-glucosidase and sucrase-isomaltase, which break down carbohydrates and facilitate their reabsorption. The PCT epithelium is also specialized for the reabsorption of amino acids, which is mediated by **transport proteins** such as sodium-glucose cotransporters.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the epithelium of the PCT is not primarily composed of goblet cells, which are found in the respiratory and gastrointestinal tracts.
**Option B:** This option is incorrect because the PCT epithelium is not characterized by a stratified squamous epithelium, which is found in areas such as the skin and esophagus.
**Option C:** This option is incorrect because the PCT epithelium is not primarily composed of simple cuboidal epithelium, which is found in areas such as the thyroid gland and adrenal cortex.

**Clinical Pearl / High-Yield Fact**
The PCT is sensitive to ischemia, and damage to this region can lead to acute kidney injury. The presence of **ischemic ATN (Acute Tubular Necrosis)** can be diagnosed by the presence of **muddy brown casts** in the urine.

**Correct Answer:** D. Simple cuboidal epithelium