Flat epithelial cells with irregular boundaries are 

Options

A. Cuboidal
B. Squamous
C. Columnar
D. Transitional

Answer

To determine which type of epithelial cells are flat with irregular boundaries, let's analyze the options provided:

1. **Cuboidal Epithelium**:
- **Shape**: Cuboidal cells are cube-shaped.
- **Boundaries**: They have regular boundaries.
- **Conclusion**: This option is incorrect.

2. **Columnar Epithelium**:
- **Shape**: Columnar cells are elongated and column-like.
- **Boundaries**: They also have regular boundaries.
- **Conclusion**: This option is incorrect.

3. **Transitional Epithelium**:
- **Shape**: Transitional cells can change shape and are not strictly flat.
- **Boundaries**: They do not have irregular boundaries.
- **Conclusion**: This option is incorrect.

4. **Squamous Epithelium**:
- **Shape**: Squamous cells are flat and scale-like.
- **Boundaries**: They have irregular boundaries.
- **Conclusion**: This option is correct.

**Final Answer**: Flat epithelial cells with irregular boundaries are **squamous epithelial cells**.