The term grey matter refers to :

Options

A. neurons that are unmyelinated
B. axons that are myelinated
C. dendrites that are myelinated
D. neurons that are myelinated

Explanation

### Step-by-Step Solution:

1. **Understanding Gray Matter**:
- Gray matter is a term used in the context of the central nervous system (CNS), which includes the brain and spinal cord. It primarily consists of neuronal cell bodies, dendrites, and unmyelinated axons.

2. **Identifying the Components of Gray Matter**:
- The key components of gray matter are:
- Neurons (cell bodies)
- Dendrites (which are typically unmyelinated)
- Unmyelinated axons

3. **Analyzing the Options**:
- **Option 1**: Neurons that are unmyelinated - This is correct because gray matter consists of neuronal cell bodies and unmyelinated axons.
- **Option 2**: Axons that are myelinated - This is incorrect as myelinated axons are found in white matter, not gray matter.
- **Option 3**: Dendrites that are myelinated - This is also incorrect since dendrites do not have a myelin sheath.
- **Option 4**: Neurons that are myelinated - This is incorrect for the same reason as option 2; myelinated neurons are part of white matter.

4. **Conclusion**:
- The correct answer is **Option 1: Neurons that are unmyelinated**. Gray matter is characterized by the presence of unmyelinated neurons, which is why this option is the right choice.