Radial vascular bundles are found in :

Options

A. dicot root
B. monocot root
C. dicot stem
D. both dicot and monocot roots

Explanation

### Step-by-Step Solution:

1. **Understanding Vascular Bundles**: Vascular bundles are the structures in plants that contain xylem and phloem, which are responsible for the transport of water, nutrients, and food.

2. **Identifying Radial Vascular Bundles**: Radial vascular bundles are characterized by the arrangement where xylem and phloem are located at different radii from the center of the bundle. This means that in a radial arrangement, xylem and phloem are positioned alternately around the central core.

3. **Location of Radial Vascular Bundles**: Radial vascular bundles are primarily found in the roots of plants. This is a key feature that distinguishes root vascular anatomy from that of stems.

4. **Types of Roots**: Both dicot and monocot plants exhibit radial vascular bundles in their roots. Therefore, the presence of radial vascular bundles is not exclusive to one type of root.

5. **Evaluating Options**:
- **Option 1: Dicot Root**: Correct, as dicot roots have radial vascular bundles.
- **Option 2: Monocot Root**: Correct, as monocot roots also have radial vascular bundles.
- **Option 3: Dicot Stem**: Incorrect, as stems do not have radial vascular bundles; they typically have collateral vascular bundles.
- **Option 4: Both Dicot and Monocot Roots**: Correct, as both types of roots possess radial vascular bundles.

6. **Conclusion**: The correct answer is that radial vascular bundles are found in both dicot and monocot roots.

### Final Answer:
Radial vascular bundles are found in both dicot and monocot roots.