Given:
1. Kupffer cells , 2. T-lymphocytes
3. B-lymphocytes , 4. Megakaryocytes
Of the above tissue macrophages are:

Options

A. 1 only
B. 1, 2 and 3 only
C. 1, 2, 3 and 4
D. 4 only

Answer

To determine which of the given cells are tissue macrophages, we need to analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understand the Definition of Macrophages**:
- Macrophages are large white blood cells that play a crucial role in the immune system by performing phagocytosis, which is the process of engulfing and digesting cellular debris and pathogens.

2. **Identify Each Cell Type**:
- **Kupffer Cells**: These are specialized macrophages located in the liver. They are responsible for filtering blood and removing pathogens and dead cells.
- **T-Lymphocytes**: These are a type of white blood cell that plays a central role in cell-mediated immunity. They are not classified as macrophages.
- **B-Lymphocytes**: These are another type of white blood cell responsible for producing antibodies. They are also not macrophages.
- **Megakaryocytes**: These are large bone marrow cells that produce platelets (thrombocytes) and are not involved in phagocytosis or classified as macrophages.

3. **Conclusion**:
- Among the listed cells, only Kupffer cells are classified as tissue macrophages. Therefore, the correct answer is option A: "first only".

### Final Answer:
The tissue macrophages among the given options are **Kupffer cells** (option A).

---