In observing epithelial cells under a microscope the cells are arranged in a single layer and look tall, narrow and the nucleus is located close to the basal side of the cell. The specimen is what type of epithelial tissue ?

Options

A. Columnar
B. Squamous
C. Stratified
D. Transtional

Explanation

To determine the type of epithelial tissue based on the provided observations, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Arrangement of Cells**: The question states that the epithelial cells are arranged in a single layer. This indicates that we are dealing with a type of epithelium that is classified as "simple" rather than "stratified."

**Hint**: Look for terms like "single layer" to identify simple epithelium.

2. **Examine the Shape of the Cells**: The cells are described as tall and narrow. This shape is characteristic of columnar epithelial cells. In contrast, squamous cells are flat, and cuboidal cells are roughly equal in height and width.

**Hint**: Pay attention to the description of the cell shape (tall and narrow) to differentiate between types of epithelial cells.

3. **Location of the Nucleus**: The nucleus is located close to the basal side of the cell. In columnar epithelium, the nucleus is typically situated towards the base of the cell, which supports the identification of the tissue type.

**Hint**: The position of the nucleus can provide clues about the type of epithelial tissue.

4. **Eliminate Incorrect Options**:
- **Squamous Epithelium**: This type is flat and would not be described as tall and narrow.
- **Stratified Epithelium**: This type consists of multiple layers, which contradicts the single-layer description.
- **Transitional Epithelium**: This type can change shape and is not described as tall and narrow.

5. **Conclusion**: Based on the observations that the cells are arranged in a single layer, are tall and narrow, and have nuclei located towards the basal side, the correct type of epithelial tissue is **simple columnar epithelium**.

### Final Answer:
The specimen is **simple columnar epithelium**.